How hard would it be to just copy and modify the packets being sent to the anti-cheat servers? Are they sent directly to the anti-cheat server or do they go back to the game server first and then get forwarded from there?
That's the first thing hackers try. The packets are almost certainly encrypted and checksum'ed in a way where tampering is immediately obvious. You end up at the same place - having to modify/hook into the game internals to bypass the anti-cheat.