A different but ruthless suggestion. If you want to be more sadistic, you can give cheaters extreme handicaps and weaknesses but still allow them to join a server.
It’s not the fact that’s he’s writing an anti-exploit script, it’s the fact that’s he’s making one that bullies the exploiter. Whether it was with good intentions or not, it shouldn’t be in his best interest to harass users. His script should just ban them, plain and simple.