What's preventing this person from using a different IP/VPN or whatever it's called? If he's that desperate to come back sooner then he could probably mount that kind of challenge. Or would it be too hard for them to go under the radar? I'm not a techie so I have no idea how any of this works.
He could use a VPN, but if this site cares at all about its security, I reckon that a VPN wouldn't be enough. There are other things that can be done in addition to using a VPN to make one's identity less identifiable, though (obviously I'm not going to say what they are).