Know anything about people who join with a player id higher than the client-limit in the server for example?
They try to invent an annoying nick as possible, to make the server kick or ban them out. Then, usually when this gets kicked or banned from the server, the server crashes with an access-violation message.

EDIT: This has been the most usual hack for me instead of lasering. I even got this one yesterday when my internet began to work again. I spent only 15 minutes with jj2 in my server, and got one of this.

I've got a renaming, laserers and some more things which I've already got enough, so I guess there has to be something to prevent at least half of these. JJ2-script should probably be done more difficult to understand or be covered with a password, or such.