actually
Unless you are a seasoned hacker, you can easily be caught. If the forum is tracking IPs, they can find out who the service provider is, and that service provider can tell which one of their users had that ip address at that certain time. If there is a reasonable concern the ISP will most likely cancel the user's account and contact local authorities if the behavior is of an illegal nature. The ISP most likely will not give out the user's info to anyone aside from law enforcement, so we may not ever know, but they will definitely not allow that kind of crap to continue.
Your intelligence is surpassed only by your ignorance.
You are more likely to fall down the stairs and break your neck if you live in a house with stairs. You are more likely to be in a car accident if you drive to work. You are more likely to be kicked in the nuts or punched in the nose if you practicing the martial arts. - Judge Pen