If it has any use... cheats could be activated in some way. Then you are no longer in a "legit" game, and are asked if it is what you want to do and to confirm it.
player: "grognegne activation"
prog: "Would you confirm that you wish to unleash the power of the grognegne?"
player: "super grognegne!!!"
prog: "grognegne activated. You are no longer in a legit world, all cheats are permitted"
See?

Temptation, differenciation between cheated/uncheated game... everything is clear and a legit game keeps its "authenticity and difference" compared to the cheated one.