It's also to stop you getting their sign-up bonuses multiple times. I set up another account at Party when I'd just started playing, because I wasn't allowed in the beginners' room any more and I kept losing at the regular tables. I managed to set the second account up OK but they phoned me immediately to say I couldn't have two accounts, and why had I done it. I said it was because I used PokerTracker and wanted a different screen name so I could differentiate between my current efforts and those when "I wasn't any good". (This was true, at least it was one of the reasons.) They asked which I wanted to shut down and I said the first one, which was fine because I could play the beginners' room again for a few weeks. Then I set one up on Empire Poker, which at the time had the same software as Party (still does) but had separate tables... then it was bought up by Party and uses the same tables. Later on I wanted to play play-money Sit and Goes, so set up another account, as Party makes it really difficult to play play-money S+Gs from a real money
account. I soon converted this account to real money so I could go on the beginners' rooms again, using a different credit card, address, and DOB (devious huh?).
So I actually have 4 Party IDs. Don't use any of them though. Party sucks ass!