Close registration and put a notice up that in order to register at the new forums you would have to send a pm to Admin in-game to pre-register or something.

The amount of impostors of late is getting pretty ridiculous.

The amount of work that would create would makes things WAY too hectic. We have over 31,000 players registered on the previous forum. Even if we get half of that coming into this forum, that'd end up causing more problems than anything.