I just cleared the backlog of user accounts. A few looked dodgy but didn't have the usual signs of bogus accounts. So keep an eye out. If you find one running amuck, do one of these things:
1) Block his/her account (Administer -- User Management -- Users. Then click the user's name from the list, click the Edit button, change status from "active" to "blocked" and submit the form).
2) PM me, letting me know the username
3) Email me about the same.