LoS BB

When you peek a player/creature, you can peeking him/her with or without noticing.
As thief you don't see the difference. But as victum, or anyone else in the room, you can see the difference. But if you look at it, when you fail to peek without being noticed all eyes will turn to you. So i'm suggesting a line that says "You feel eyes staring at you" or something like that

Or maybe it's more fun to just not know, keeps the thief uncertain and more wary after peeking.