Is there not some vBulletin add on that would help reduce spam accounts? I would have thought that vBulletin would have done their own, or some third party add on. It's not like spam is unique to EN World, so there must be something out there?
There are many dozens, and we use many of them. Spammers evolve. The current one is one called "bio man" which currently isn't stopped by existing measures, although I am expecting a plug-in for it today.