I just thought about something. If you have a game, mw3 for an example on a account without any kind of ban, like VAC, and you give access to your steam libary to a maximum of 5 other accounts, then you would be able to play mw3 online on the 5 other accounts, with cheats on, and if you got banned on the accounts with access, then you still be able to play legit on the original account, right? or did Valve think of that and patch it?
Just a theory, because I know you can´t give access to ther accounts, get banned on the original account, and then play on the shared accounts. VAC somehow block the family sharing thing, lel!