[djbaxter]

Originally Posted by JesterP

When they use your contact us form, reply with this:

Hello there,

If the system is telling you that you are a spammer, please try again with a different username.   There is a chance that your name choice is blacklisted in  a third-party database we subscribe to.

If you'd like, you could go to http://www.stopforumspam.com/search.php and search for your information to see why you might have been restricted.

Thank you

9 times out of ten, they come back and register.

A better solution is not to screen member names. Way too many false positives. Just check email and IP address.