Maybe there needs to be partial success to scan. Where you can detect the presence and set watch on it. But you cant target it with anything else and the sdesc/mdesc is not displayed. This way people know someone's in the room, they just cant quiet find them. This way, the sneaky knows he's been found out, but yet located and he knows it's time to get out of there, instead of continuing on with other stealth skills.
Or ... next time someone gets repeatedly failed steal on, they should just file a player complaint on.