"Cannot Register" in ban options

[Hawkk]

What does this do?  I've searched for it in FAQ and the forums and I find nothing.

It doesn't make sense if it keeps the user from registering -- isn't the user already registered?  Why ban a registration for a username?  Or is that only for an IP range?

Thanks.

[[Unknown]]

It's really only for email (%@hotmail.com) or IP ranges... although I think it may have a wildcard effect on usernames, I can't remember just now.

-[Unknown]