I think its already confirmed that if your bitcointalk account is hacked and used to scam then you are responsible. At least that's what I've always thought and what would be the most reasonable in my opinion. It seems there is some confusion though when using a 3rd party source of communication and it gets hacked and used to scam, people think they aren't responsible. In my opinion you're the one taking the risk and you should be held responsible, not the unsuspecting victim. It also opens the doors to fake scam attempts.