If someone wanna play Paintball, he must check the rules, and if agree or not. If you are not able to respect those rules, you should not play.
A black list would be a good way to get it an end.
By the way, if They knew the rules and hacked they must be banned, not from his own server but pub servers.
Doesn't matter if it was for fun or not, they hacked.
Oh, hacking is pathetic.