A question entered my mind as I played a little football today. As has been pointed out before, an accurate simulation of human intelligence would be capable of mistakes. But do you think gamers can ever be expected to perceive the mistakes of their NPC companions and teammates as acceptable... or even realistic?
Frankly, I doubt it.
When an NFL wide receiver doesn't catch a pass, when a World Cup goalie loses sight of a corner kick, when a basketball player misses a free throw... fans, in my experience, are generally not very forgiving. Most fans don't think "Well, even a professional's going to mess up sometimes... ". No, they think more along the lines of "C'mon, you idiot! Even I could have caught that!". Right?
If most people don't keep in mind that even the best trained and most experienced veterans will mess up and have off days, then how could we possibly expect gamers to accept mistakes from NPCs... even if those mistakes are intentionally included as realistic variables?
Every long-time gamer has had an experience that makes us say "the game cheated". Sometimes, we're right. Games do cheat. But it's often the same sort of response as yelling "Catch the freakin' ball!" while watching our favorite quarterback shake his head in disbelief (even the players have trouble accepting mistakes). We habitually choose to believe the simplest answer, rather than the truth.
If we're so willing to doubt our flesh-and-blood comrades, then NPCs don't stand a chance in hell.