How to stop people from hacking on Garry's mod

Anything made by humans can be broken by them.
An AntiCheat is in no way an exception to that sadly...
If there's a game that doesn't have that good of an anticheat built onto it on both the server and client side then sadly there's no real way of stopping them.
Garrys Mod needs some kind of a VAC, but I realize that it might come with a fuckload of false-positives just due to the nature of some addons...