Admins Detecting Hacks?

So I've been using mPaex² (Garry's Mod Hack obviously) and I've been banned on a couple of servers, right after the admin start spectating me, they can see the hacks, I don't know how they can. I usually try to leave because I can't turn off the hack after activating it, so I resort to leaving the game, I know it's a dumb move mostly because I can't think of anything else to do. Usually they pm me or tell the server "I can see your hacks"

So is there a hack that I can use to hide the hacks when people spectate me?

-cough- I'm new to forums so hi.

They probably grab your screen. And see the visual hacks like esp.