[kh99]

I think the answer is that you can't do anything about it. There are ways to get a different ip or to use a proxy (and not all of them can be detected by a "proxy detector" mod). And even if you're requiring credit cards, it's probably not too hard for most people to get someone else to pay or something. I suppose you could try verifying people by phone or snail mail or something, but that's a lot of work. If the users were banned just because of behavior, then my suggestion would be to not worry about it until/unless they start with the same behavior again (don't let yourself get caught up by the idea that it's a game you have to win, because you can't). If it's some other issue, then I don't think there's a lot you can do.

Edit: about the 10.... ip - I don't know how that happens. That's an ip address that can't be used on the internet (it's for use in a private network). In any case, it won't tell you anything about who used it.