Anti cheating is pointless. Any halfway competent FREDder could remove your convoluted anti-cheating method in seconds.
Not to mention that someone could simply run a debug build and activate the cheats without typing in the code.
While stopping in game cheating is a good idea (making sure the player can't find an easy way to blow up the enemy by getting his wingmen to do it or something) is worth doing, when dealing with the cheat codes you're dealing with someone who has deliberately decided to cheat at your mission, not simply exploited a flaw in it. Trying to prevent them is a waste of time.