@Don Von Alpha Dom
I'm not fully sure, but since Imvu tracks/bans using bluecava, which you can opt out of on bluecava's site making you untrackable via pc specs, I assume its something like that. Or the fact that smart ppl will do it on a dummy pc since they know that its you pc that get banned and not your ip. Locations are also a factor, imvu does track your location, so if the locations of the dummy accounts are not the same as yours I think they let it slide. But if it happens too often thats when they get fed up. So if you have a hater, they'd have to be persistent to get you banned.
I also think that there are not enough cases of this happening for imvu to think about this.
Keep in mind that if you make a ton of accounts and they are all guests, they look less legitimate. If you want multi accounts, I suggest buying the names at least. And don't sit there and do it back to back DUH! Let some time pass, because when they look at your log (AND THEY DO) they will know what you did, because that looks suspect.