Well, Mortal Magic currently hexes things in the Dresdenverse.  That doesn't rule out some form of Sponsored Magic, perhaps from some god or spirit of technology, that has manipulating technology as an aspect.

If your an evil warlock with a sense of humor yes that just might make your day, if your a creature from the never never then it would be someone elses problem.

Can't speak for creatures for the Nevernever, but an evil warlock that killed a specific individual for a reason like "in order to inherit his money" or "to eliminate a rival for the object of my affection's love" might find it inconvenient if a spirit wearing the person's body came into the picture and usurped the person's place.

The rules simply say armor provides armor.  I think it would be a little unfair to armor wearing characters, espeically Pure Mortals who have to rely on equipment to have any chance of contending with some supernatural foes, to generically penalize them in all situations beyond the rules.

That said, if you want someone to take advantage of the fact that someone is wearing kevlar, Assessments and Declarations are the way to go.  NPC's like cops or criminals could make an Assessment noticing someone is wearing a vest, thus they know he's expecting trouble and to watch him closely.  And a foe could make Declarations like "Hot and Distracting" to get a bonus to certain types of actions and maneuvers where it would be appropriate to get an advantage from that aspect.

Originally from the Human Prince of Faerie thread

Peter Walker (Feet In The Water)
High Concept:  "Teen Prince of The Neighborhood Pixies"
Trouble: "My Secret Life"
Other Aspects: "Parents' Pride And Joy," "Channeling The Inner Hero," "My Complex Love Life," "A Faerie Tale Education," "A Knack For Bargains"

Skills:
Good (+3): Conviction, Fists, Presence
Fair (+2): Discipline, Rapport, Scholarship
Average (+1): Alertness, Deceit, Empathy, Endurance, Lore

Stress:
Mental: OOOO
Physical: OOO
Social: OOOO

Powers:
Faerie Crown [Item of Power]
     One Time Discount [+2]
     Indestructible [+0]
     Glamours [-2]
     Light Source (See Pixie entry, page 48 of Our World) [-0]
     Supenatural Recovery [-4]
     The Catch: Cold Iron [Easily Accessible +2; Specific Research Material Necessary (not everyone is aware humans can become Princes of Faerie) +1]

Final Cost [-1]

Stunts:
Footwork
Martial Artist
Armed Arts: Gun (Staff) and Dao (Sword)  (Note that Dao training can be applied to similarly sized objects such as canes or baseball bats)
Redirected Force

Refresh: 1

High Concept: "Teen Prince Of The Neighborhood Pixies"
Peter is an ordinary teenage kid who just happens to be Crown Prince of a tribe of pixies which has settled in his part of town.  Which means not only does he get to deal with all the normal things in a teenager's existence, good and bad, but all the rights, privileges and responsibilities of being the leader to a group of faeries on top of that.  Talk about a full plate!
Invoke: as a bonus to any activities related to fufilling his Princely duties, as a bonus to anything done being done in the capacity of an ordinary teenager, for effect to have his subjects do something significantly onerous or dangerous for him
Compel: to have Peter's responsibilities as Prince complicate his life; to have typical teen limitations and concerns complicate Peter's activities or involvement with supernatural matters.

Trouble: "My Secret Life"
There are a lot of people in Peter's life who are clueless about the supernatural in general, let alone Peter's Princedom.  Teachers, friends, classmates, and most importantly, his parents.  Peter would like to keep it that way to avoid freaking them out.  Unfortunately, keeping the supernatural side of the world from being discovered is a lot harder when your involved with it in a major way.  Luckily, he can get help from his sister Lucy and his best friend since kindergarten Jane to protect the clueless people in his life from the truth.
Invoke: as a bonus when trying to hide or explain away supernatural creatures or incidents to the clueless, as a bonus to attempts to convince supernatural beings to cooperate with attempts to keeping the supernatural secret
Compel: to have supernatural beings visit or incidents occur while there's a chance that a clueless person in Peter's life could potentially notice

Background: "Parents' Pride And Joy"
The elder of two children, Peter is the son of Frank and Janet Walker.  His father is a senior surveyor and civil engineer for the city, while his mother is a Park Ranger.  His sister Kate is two years younger than him.  Growing up, he's always been supported and encouraged by his parents to achieve both at academics and extracurricular activities.  And it's paid off.  Peter has excelled academically, regularly placing on the honor roll.  And when movies got Peter interested in learning kung fu, his parents sprung for lessons from the best instructors in the city, and proudly display the trophies he's won in various regional competitions. 

Despite all their attention and indulgences, Frank and Janet set fair but firm rules that they expected Peter to follow.  This positive encourgement coupled with an adequate discipline shaped Peter to be a good kid.  This of course was another source of pride for his parents.  While other parents had problem children who got into various kinds of trouble their son was a good kid.  Of course, being a good kid, Peter feels obligated to live up to his parents opinions and expectations and avoid doing things that would disappoint them.
Invoke: as a bonus to social interaction with his parents; for effect to declare that he has something due to it being provided by his parents.
Compel: to have Peter do something in order to live up to his parent's expectations or to avoid disappointing them.

Rising Conflict: "Channeling The Inner Hero"
It seemed for a time that Peter Walker was going to have a nice but ordinary life.  Then came the summer he first met the pixies.  It started one day when he was sitting out on the deck eating pizza.  He had gone back inside just for a second to get a drink and when he came back outside there was a tiny, winged figure munching on the slice on his plate.  She quickly noticed his return and flitted away rapidly.

At first Peter just wanted to brush off the experience as an overactive imagination, but then curiosity got the better of him.  He began leaving a piece of pizza out every night, only to find the next morning it was entirely gone.  After a few nights, he decided to stay up and wait.  His patience was rewarded by the sight of several of the winged figures flying up to feast on the pizza he had left for them.  He went out to get a closer look at them, and while most flew away quickly this time one decided to stay when he asked.  That night an arrangement was forged in which the pixies would stay and answer questions in return for pizza.

The rest of the summer he would out with the pixies, sharing pizza with them and learning about Faerie and other aspects of the supernatural world.  Peter and the pixies became friends, and he ended up helping their community in other ways.  Then one day, a week or so before the beginning of the school year, terror came to the neighborhood pixie tribe in the form of a young malk.  The faerie predator had stumbled upon the tribe and became determined to hunt them all down and eat them. 

When Peter heard about this he knew he could not let that happen to his friends.  Giving the pixies sanctuary in his room, he went out with his bo staff to try to convince the malk to leave.  But the malk, unwilling to give up his prey, could not be persuaded to go.  It in fact threatened to add Peter to that category if he did not invite him inside and let him hunt. 

Realizing the only way to insure the long term safety of his friends was to fight, Peter attacked the malk despite how dangerous he knew it was.  It was a tough, and vicious fight, but in the end Peter triumphed thanks to his determination and training.  Grateful for Peter's defense of them and impressed with his willingness to risk life and limb on their behalf, the pixie tribe decided to make him their Crown Prince.  And thus began the next, stranger and more exciting chapter in Peter's life.
Invoke: as a bonus anytime Peter is doing something difficult or dangerous for the sake of another, as a bonus to social interaction with anyone aware of his heroic deeds.
Compel: to have a circumstance or event arise in which Peter will have to act in a heroic manner to prevent others from being hurt.

First Story - Save Me A Dance: "My Complex Love Life"
So the school is throwing a dance and Peter's trying to figure out who to take.  He has a crush on this girl named Georgia in is home room, but he's not even sure she knows he exists.  Then there's Jane, who suggested they be each other's back-up "safety dates" in case they couldn't get real ones, but he's not exactly sure how he feels about that.  Of course, being a Prince of Faerie, Peter's girl problems do not stay confined to the safe and mundane.  It seems Aiela, a young nymph, has her heart set on a having the True Love of a Prince and has set her sights on him, going so far as to adopt the identiy of a human girl and start attending his high school in pursuit of him.  Oh, and then there's the fact that Peter's subjects have decided to help their Prince get the girl, only they're divided as to which girl is the right one and have split into different "teams," each trying to make sure that Peter ends up with their choice for best match.
Invoke: as a bonus to social interaction with potential romantic interests, as a bonus to anything done to help or protect a potential romantic interest.
Compel: to have a potential love interest complicate his life in some way, to have his pixie subjects complicate his life with well-meaning "help" in regards to his love life.

Guest Star Spot - Insert Story From Fellow Party Member Here: "A Faerie Tale Education"
Peter has learned most of what he knows about the supernatural from his subjects.  Which has its advantages and disadvantages.  Any story that one ties this aspect to should have those things be a factor in Peter's involvement.
Invoke: as a bonus to Lore rolls for matters pertaining to faerie, as a bonus to social interaction with faeries thanks to tutoring on faerie ettiquette and culture, as a bonus to Contact rolls involving faeries or people tied to faeries in some way, for effect to declare a fact or circumstance that would derive from knowledge of Faerie
Compel: have knowledge or attitudes about beings, organizations, or prominenent individuals in the Supernatural World influenced by the perspectives and biases held by his subjects

Guest Star Spot Redux - Insert Story From Fellow Party Member Here: "A Knack For Bargains"
One thing one picks up early when dealing with Faerie is the importance the place on bargains.  Peter has learned that lesson well, and is very careful when it comes to making them.  Any story that one ties to this aspect should have a bargain or bargaining be a factor in Peter's involvement
Invoke: as a bonus to convince someone to make a bargain, to negotiate favorable terms for a bargain, to assess any loopholes that can be found in a bargain; for effect to declare that Peter is calling upon the terms of a past bargain for something.
Compel: when the terms of a bargain that Peter has made complicates a situation he is in.

Peter Walker
High Concept:  "Teen Prince of The Neighborhood Pixies"
Trouble: "My Secret Life"
Other Aspects: "Parents' Pride And Joy," "Channeling The Inner Hero," "My Complex Love Life," "A Faerie Tale Education," "A Knack For Bargains"

Skills:
Good (+3): Conviction, Fists, Presence
Fair (+2): Discipline, Rapport, Scholarship
Average (+1): Alertness, Deceit, Empathy, Endurance, Lore

Stress:
Mental: OOOO
Physical: OOO
Social: OOOO

Powers:
Faerie Crown [Item of Power]
     One Time Discount [+2]
     Indestructible [+0]
     Glamours [-2]
     Light Source (See Pixie entry, page 48 of Our World) [-0]
     Supenatural Recovery [-4]
     The Catch: Cold Iron [Easily Accessible +2; Specific Research Material Necessary (not everyone is aware humans can become Princes of Faerie) +1]

Final Cost [-1]

Stunts:
Footwork
Martial Artist
Armed Arts: Gun (Staff) and Dao (Sword)  (Note that Dao training can be applied to similarly sized objects such as canes or baseball bats)
Redirected Force

Refresh: 1

High Concept: "Teen Prince Of The Neighborhood Pixies"
Peter is an ordinary teenage kid who just happens to be Crown Prince of a tribe of pixies which has settled in his part of town.  Which means not only does he get to deal with all the normal things in a teenager's existence, good and bad, but all the rights, privileges and responsibilities of being the leader to a group of faeries on top of that.  Talk about a full plate!
Invoke: as a bonus to any activities related to fufilling his Princely duties, as a bonus to anything done being done in the capacity of an ordinary teenager, for effect to have his subjects do something significantly onerous or dangerous for him
Compel: to have Peter's responsibilities as Prince complicate his life; to have typical teen limitations and concerns complicate Peter's activities or involvement with supernatural matters.

Trouble: "My Secret Life"
There are a lot of people in Peter's life who are clueless about the supernatural in general, let alone Peter's Princedom.  Teachers, friends, classmates, and most importantly, his parents.  Peter would like to keep it that way to avoid freaking them out.  Unfortunately, keeping the supernatural side of the world from being discovered is a lot harder when your involved with it in a major way.  Luckily, he can get help from his sister Lucy and his best friend since kindergarten Jane to protect the clueless people in his life from the truth.
Invoke: as a bonus when trying to hide or explain away supernatural creatures or incidents to the clueless, as a bonus to attempts to convince supernatural beings to cooperate with attempts to keeping the supernatural secret
Compel: to have supernatural beings visit or incidents occur while there's a chance that a clueless person in Peter's life could potentially notice

Background: "Parents' Pride And Joy"
The elder of two children, Peter is the son of Frank and Janet Walker.  His father is a senior surveyor and civil engineer for the city, while his mother is a Park Ranger.  His sister Kate is two years younger than him.  Growing up, he's always been supported and encouraged by his parents to achieve both at academics and extracurricular activities.  And it's paid off.  Peter has excelled academically, regularly placing on the honor roll.  And when movies got Peter interested in learning kung fu, his parents sprung for lessons from the best instructors in the city, and proudly display the trophies he's won in various regional competitions.  

Despite all their attention and indulgences, Frank and Janet set fair but firm rules that they expected Peter to follow.  This positive encourgement coupled with an adequate discipline shaped Peter to be a good kid.  This of course was another source of pride for his parents.  While other parents had problem children who got into various kinds of trouble their son was a good kid.  Of course, being a good kid, Peter feels obligated to live up to his parents opinions and expectations and avoid doing things that would disappoint them.
Invoke: as a bonus to social interaction with his parents; for effect to declare that he has something due to it being provided by his parents.
Compel: to have Peter do something in order to live up to his parent's expectations or to avoid disappointing them.

Rising Conflict: "Channeling The Inner Hero"
It seemed for a time that Peter Walker was going to have a nice but ordinary life.  Then came the summer he first met the pixies.  It started one day when he was sitting out on the deck eating pizza.  He had gone back inside just for a second to get a drink and when he came back outside there was a tiny, winged figure munching on the slice on his plate.  She quickly noticed his return and flitted away rapidly.

At first Peter just wanted to brush off the experience as an overactive imagination, but then curiosity got the better of him.  He began leaving a piece of pizza out every night, only to find the next morning it was entirely gone.  After a few nights, he decided to stay up and wait.  His patience was rewarded by the sight of several of the winged figures flying up to feast on the pizza he had left for them.  He went out to get a closer look at them, and while most flew away quickly this time one decided to stay when he asked.  That night an arrangement was forged in which the pixies would stay and answer questions in return for pizza.

The rest of the summer he would out with the pixies, sharing pizza with them and learning about Faerie and other aspects of the supernatural world.  Peter and the pixies became friends, and he ended up helping their community in other ways.  Then one day, a week or so before the beginning of the school year, terror came to the neighborhood pixie tribe in the form of a young malk.  The faerie predator had stumbled upon the tribe and became determined to hunt them all down and eat them.  

When Peter heard about this he knew he could not let that happen to his friends.  Giving the pixies sanctuary in his room, he went out with his bo staff to try to convince the malk to leave.  But the malk, unwilling to give up his prey, could not be persuaded to go.  It in fact threatened to add Peter to that category if he did not invite him inside and let him hunt.  

Realizing the only way to insure the long term safety of his friends was to fight, Peter attacked the malk despite how dangerous he knew it was.  It was a tough, and vicious fight, but in the end Peter triumphed thanks to his determination and training.  Grateful for Peter's defense of them and impressed with his willingness to risk life and limb on their behalf, the pixie tribe decided to make him their Crown Prince.  And thus began the next, stranger and more exciting chapter in Peter's life.
Invoke: as a bonus anytime Peter is doing something difficult or dangerous for the sake of another, as a bonus to social interaction with anyone aware of his heroic deeds.
Compel: to have a circumstance or event arise in which Peter will have to act in a heroic manner to prevent others from being hurt.

First Story - Save Me A Dance: "My Complex Love Life"
So the school is throwing a dance and Peter's trying to figure out who to take.  He has a crush on this girl named Georgia in is home room, but he's not even sure she knows he exists.  Then there's Jane, who suggested they be each other's back-up "safety dates" in case they couldn't get real ones, but he's not exactly sure how he feels about that.  Of course, being a Prince of Faerie, Peter's girl problems do not stay confined to the safe and mundane.  It seems Aiela, a young nymph, has her heart set on a having the True Love of a Prince and has set her sights on him, going so far as to adopt the identiy of a human girl and start attending his high school in pursuit of him.  Oh, and then there's the fact that Peter's subjects have decided to help their Prince get the girl, only they're divided as to which girl is the right one and have split into different "teams," each trying to make sure that Peter ends up with their choice for best match.
Invoke: as a bonus to social interaction with potential romantic interests, as a bonus to anything done to help or protect a potential romantic interest.
Compel: to have a potential love interest complicate his life in some way, to have his pixie subjects complicate his life with well-meaning "help" in regards to his love life.

Guest Star Spot - Insert Story From Fellow Party Member Here: "A Faerie Tale Education"
Peter has learned most of what he knows about the supernatural from his subjects.  Which has its advantages and disadvantages.  Any story that one ties this aspect to should have those things be a factor in Peter's involvement.
Invoke: as a bonus to Lore rolls for matters pertaining to faerie, as a bonus to social interaction with faeries thanks to tutoring on faerie ettiquette and culture, as a bonus to Contact rolls involving faeries or people tied to faeries in some way, for effect to declare a fact or circumstance that would derive from knowledge of Faerie
Compel: have knowledge or attitudes about beings, organizations, or prominenent individuals in the Supernatural World influenced by the perspectives and biases held by his subjects

Guest Star Spot Redux - Insert Story From Fellow Party Member Here: "A Knack For Bargains"
One thing one picks up early when dealing with Faerie is the importance the place on bargains.  Peter has learned that lesson well, and is very careful when it comes to making them.  Any story that one ties to this aspect should have a bargain or bargaining be a factor in Peter's involvement
Invoke: as a bonus to convince someone to make a bargain, to negotiate favorable terms for a bargain, to assess any loopholes that can be found in a bargain; for effect to declare that Peter is calling upon the terms of a past bargain for something.
Compel: when the terms of a bargain that Peter has made complicates a situation he is in.

They'll probably have actual rules for it when the Paranet Files supplement comes out, but till then you could probably get by with it  either being a form of Sponsored Magic that among other things lets you use Divination at evocation speeds, but only of the area the Genus Loci encompasses. or a Supernatural Sense that gives one information on everthing in the Loci.

Of course, it's been a few months since I read Turncoat so there might be some abilities granted by being attuned to a Genus Loci that I had forgotten.

Why, The Za! Court of course!