Private Message Spam

[Sacks]

I'm not sure if what I received just now is the same thing, but it certainly looks similar to what has been going on on some other forums. Accounts with names like SYSTEMADMIN or DUDEGUYMODERATOR send private messages and if you open them you get all kinds of diseases and send everyone in your contacts list a bunch of emails or something. Is there any way you can ban the use of "admin" or "moderator" in usernames to stop this bullshit?