[manning]

It doesnt stop them because they have scripting that is bypassing the entire register process - least thats my best guess.

Vbulletin should have a fix for this - its getting really bad on one of my forums too the last few months. I have installed a few mods and it really slows them down, but a few still manage to get through. Its very annoying.

I use NO SPAM linked above in addition to this > Stop the Registration Bots and it sends me an email every time it denies a registration - a good deal of these dang bots complete the form in 0 seconds - no way they are even looking at it - they are pretty much inserting straight to the db some how.

Another mod I suggest is the SM Limit Editing Signature Before X Posts - this prevents anyone from having access to the signature until they have X number of post. Least when they do get through they wont be able to do anything with the account!