DJChris what did you base your bans on? A lot of times people will just sign up for bragging right. " I belong to 500 forums dude. Top that." That sort of stupid crap.
I'm gonna put you on to a couple of handy tools to double check your work with.
1. This on going thread at vbullentin.com > http://www.vbulletin.com/forum/showthread.php?t=275885