yes i totally agree, on all my forums i can check the IP of any member, its very useful for giving the IP the once over in Google checking for known spammers. so yes it would be a great idea, stop some people right in their tracks.
LOL@ lightwolf, so youve noticed too have you that a certain member defo has more than one account try several (mind you, its one way to get friends when you have non i suppose) LOL...

regards

Tyke