Question about registering to forums?

Okay so I have an account registered on a forum, i want to make another one though (for a few reasons) but the forums rules says you cant make 2 accounts (a.k.a alias) obviously they can find out if i have two accounts because they can see if those accounts have the same I.P., so my question is that what if i go to my friends house and register there (since it's different I.P's and everything) would they find out its me? or not? if so how?