RoryOF suggested I RTFM, but I'm too lazy for that

I was hoping someone else would look into it.
Seriously, every time I try to improve my (negligible) phpBB knowledge by reading the manual, I just get more confused.
One thing did pop out though, maybe the way to do it is to create a "monitored users" group that would be subject to moderation and/or more restrictive permissions for links/signature, etc. I think it's fairly easy for a moderator to assign/add a user to a group, and that would take care of the permissions. I just don't know if it's hard to create a group, or if you can do it based on another group--this group is the same as a registered user but should be moderated for all posts.
Or, we could keep everything simple and just nuke the b_____d and see if anyone complains
