What do you think hacking is? The actual laws broken were "unauthorized access to computers and computer networks." If you know that you don't belong on a system (like being B&), and you get on the system anyway (unlawful access), you could be V&. Find out about that, it's kind of creepy. Google it.
Again, I'm not saying that anyone will go after some kid d*cking around on a forum, but the laws are there. No need to bring China into this.
*Getting B& is not a crime, but logging on after being banned is. Just because something is a crime doesn't mean that you will surely get punished, only that you *could*, if things go wrong. And i'm pretty sure you knew what i meant without me typing an essay about it.
Holy hell thanks for the laugh. There is no hacking going on by joining a forum over and over. None. There could be charge pressed if they accessed the admin panel and removed the ban, and you could prove it; or they are making some kind of death threats and the like. There is no illegal activity in being a troll on a forum. You have to ban the IP and so forth to mitigate the trolls/spambots and so forth.
I would love to see a case where a forum owner sued a troll tho. That would be classic.
FYI, here you go since you were too lazy to link it yourself.
http://www.expertlaw.com/forums/showthread.php?t=96783