So... as an avid gamer and BIG fan of everything Jim Butcher I was compelled to look into this thread and on the sites of the RPG... And something came to mind.

Can you Violate someone's mind if they ask you in?  At least as the laws put it?  I know that SOME Wardens would say that entering anothers mind, willing or no, puts you on that path... but consider if someone has a habit or something that they know is hurting/killing them and ASKS the wizard for help. 

Would it be a violation if they knew this was something you were capable of and asked for your assistance?  I know intent is a major thing and from the description of certain things in Dead Beat it would still have major problems.  ... instead of asking to be allowed to help... And there is other background to suggest other reasons for the "wounds" to look as they did.

And if the invitation thing applies... it would suggest the possibility of a means of training mental defenses.  Seeing as critters from the Nevernever can and will violate ones mind... and pushing/fighting them till they're out seems to be the primary means of defense.

Take the previous example of a cabal of younger wizards learning the tricks of the trade hearing about someone who's will was co-opted til a warden came to deal with the warlock/sorcerer.  Taking a look at the laws they say "Hey... if we practice with each other on pushing or keeping each other out for a very specific purpose... we might be able to develop techniques to help against that."  And, if we say they all agree to the terms they set out and stick by them for the purpose of this training they've come up with...
One could ARGUE that they held up the terms of the law while practicing a defense against it.   Granted... discovery that they'd done so would likely get them killed by the old guard Wardens... but most kids are convinced of their immortality anyway.

Just some thoughts to ponder and argue.