Precisely, the wonderful thing about PBBans, is that bans are not backed up by accusations, or assumptions, but by 100% concrete evidence. It's good for both PBBans, and for the users, even if it may cause some problems because some proof cannot be proved. It's the best way this way, and I wouldn't have it any other way.
Anyways, it appears that I'm completely off topic now, and this topic has already been answered lol.
People, always read the ToS's, I once encountered a site where their ToS and Privacy Policy was "when you sign up here, you are giving permission to the owners of the site to steal all your information, and use it in anyway they want", it said it just like that (not in those words, but the same idea). It turns out that I happened to read their ToS AFTER I signed up. <_<