Wow, cool idea. I would like to play a game like this, centered on deception and borderline-voyeurism. I would be even more impressed if such a game opened the way to counter-deception.
Imagine this: around halfway through the game, you, Mr. or Ms. Invisible, are approaching the target of a difficult mission - some sort of object or information. You have crept into a room, but an enemy character is inside too. Until now, the guards have reacted to any sounds you made with confusion and suspicion, but they haven't realized that an invisible enemy is among them. This character, however, knows (but you don't know he knows - not yet, anyway). At first, this character seems particularly thick, since he barely reacts to any noises you make or furniture you jostle. This enemy keeps up a calm facade until you get too close - then he whips around and wrestles your invisible self to the floor.
Maybe the game could be set up to ensure the player survives this (pants-soiling) encounter, but ever after, some of the enemies would feign ignorance when they suspect you, and you'd have to watch closely if you needed to determine whether you were safe or whether they were faking it, and this ambiguity could be incorporated into the story too.
Such mind-fuckery could turn a game from something resembling a spy fantasy into something resembling Philip K. Dick's nightmares (They know. Or do they? Maybe they are just pretending to know? They know I know they know. Which is what they want... maybe? Because there's something worse that I don't know?) No video game can permanently outsmart a human player, but I think it's cool when they try, and pretty amazing when they succeed. A game that is all about trickery would have lots of opportunities for that, I think.