Just ban them :P Simple as that....and you could get plugins like NoCheat and NoCheat+

boo no explosion, well that sucked. The guy doesn't hack, he cheats, enless he actually made the program. Just because he has the hack client doesn't mean he hacks, it means he is a cheater. I have made previous hack clients for myself but I was the owner of the server and they only helped me and it wasn't for an advantage. Cheaters don't care but hackers like the money. Call me a hacker idc I take it as a compliment. If you don't hate, then you're a hacker? What if some one doesn't care about hackers? Indeed it's called cheating not hacking. A plan to stop hackers? That is why anti-hackclient plugins exist like no cheat and more. Or did you not remember those? You can't stop us from making money and you can't get rid of us. We usually don't harm anyone ever.