Hmm I don't think GL has a ban by user, email, or ip address function
(maybe this could be a feature request). But I'd do it either by moving
the offensive users to a group and restricting that group's abilities so
they cannot submit anything, etc. This would prevent them from signing
up again with the same e-mail address and from posting anything you
don't want.
One other option you have is to delete all those users, and hide the
login block to anoymous users.
Yet another way to go about it is to turn on the user submission
queue, delete the current nefarious users, and simply deny any new
signups unless you know who it is from.
---
L. Whitworth
www.finiserv.com
L. Whitworth