Buddypress Fake (non-bot) Users [closed]

BuddyPress Newbie question:

I have a brand new site running WP 3.3.1 and BP 1.5. Even before launch I am plagued with numerous fake users every day. I don’t think they are bots, because I have a math question at registration, and email activation enabled. They register, usually with a gmail address, and then activate and post updates containing spam links of all sorts.

I haven’t been able to find any real ideas on how to stop non-bot spammers, and have pretty much given up on an automated solution. Barring that, is there a way to hold new users for admin approval and prevent them from posting until they are approved?

Any solutions are greatly appreciated!
Thanks!
Diana

Fake registerion to buddypress is a real pain in the !@$ (pardon my french).
I’ve tried math question, captch, sabre and other plugins but none of them seem to work.

So far, only WangGuard did the trick. It won’t give you full protection against those registrations but it’s the most efficient tool I’ve found against them.