You know how a bot insta bans you when you join DMU with a hack client? Some people may accidentally may have a hack client still in the mod file on accident (Who knows, they probably were using it on a single player world?), but Im not saying all people have it accidentally. Anyways, if it is possible, before joining the server, if a hack client is detected, a warning screen will pop up saying that a hack client has been detected and if they don't want to be banned they will be prompted to go to their mod file and remove it before the joining. If they ignore the message and join the server with the client, they'll of course, be banned.

Not a bad idea