This actually brings to mind another "What If" I've been considering...
What if a wizard were to erect magic circles around certain bits of technology... say for example, the water heater in their house? It's been used in canon: Butters using a magic circle to shield a GPS unit from Harry and the latent magics surrounding the Darkhollow.
So, say random wizard has a television set up in his home and has someone put a magic circle around it before he begins setting up his wards and work-space, would he be able to regularly use said TV (even though he'd probably have to buy a new remote control about once a month)?
Just a thought. ^_^
I do not have the book with me: In Blood Rites, did the pornstar sorceresses with their sponsored magic accidentally hex anything?
I think that the group has to decide for themselves certain issues:
1) What is mortal magic? (Does Sponsored Magic count when used by a mortal?)
2) What is a mortal? (How does free will count/does not count for "mortality"?)
3) Does other manifestations of supernatural powers by mortals count as mortal magic?