What if someone was using you account to play a game and they got vac banned? Like if you have friends over your house. You can not always confirm who did it and that it was not a false positive.
Thats your fault for trusting "your friend"?
Seriously if I had friends that would risk my game account like that well first off they would no longer be friends, 2nd it would be my fault for being naive enough to let them use my account in the first place.
But this is a mute point least in my case as I never let anyone use my accounts, the only exception I could see for deserving a vac ban reversal would be if the account was hacked.