There's a guy at work (you guessed it, his name's Adam) who uses one of those kneeling computer chairs. However, he also likes to sit really low in it, which hides him behind the giant monitors and a half-wall that runs right next to his desk. People come in all the time and start talking to him, only to find that he isn't there. It's a much larger source of frustration than you might think.
The Adam Detector relieves the frustration by providing an indicator light, making it quickly apparent whether or not Adam is at his desk.