If they do open up another account then they will need to:
Hide their IP (slight deterant I guess)
NOT identify themselves, and hence cant talk about their car etc (after all if "billy joe jimbob" signed up with a yellow 3door on escos rims it would be obvious it was me etc)
Behave or that account will get banned too


So I dont think its "pointless" I just think its just a fact that on the net, if you want to pretend to be two people its not possible to identify you if you bother to do a good job of it.