Hmmm, did Grim really mean "free" public hack? That's a different thing than a "paid public hack like AA". For a true "free" public hack, I'd expect next to nothing, if not to be detected the first time I use it!
For a paid hack, I expect about what I get from my Master Pack here at AA!
First and foremost in a private hack (that I'd likely pay out the @$$ for!) I fully expect the coder to use UNIQUE code thereby reducing the likelihood of PB, VAC, etc. putting it on their "signature radar." If its good code, and I'm the only one with it (or at least one of less than a hundred or so) then I'd expect it MUCH less likely to be detected.
Would I pay for this? Probably, but only for the first few months after release of a game - we've all seen how detections seem to decline after the first few months; whether that's because the hax get better or the detection becomes less lucrative for the game/cheat detection companies is anyone's guess.