I'm seeing an awesome scenario like from The Godfather 2. Vito twists the bulb in the light so it goes out. Guy goes to check it and BOOM!! Vito paints the walls with the guys brains. It would be awesome if baddies would investigate lights that go out only to be snuffed out themselves!
Thats what NPCs did in THIEF Deadly Shadows. Or even a little bit of noise, like knocking over a candel. You could shoot a Noise Maker arrow which would make a hell of a racket and anyone near by would rush over to it to investigate, and then would start looking around where the arrow might have come from. It was a hard game. But you coulld use that as an advantage to lure guards out of rooms or look the other way which you sneak right behind them. It was a realy wel done game.
"I didnt open this door, I thinks some one bees around here opening doorsies"
"Ahh, Me thinks its bees rats again."
"Hey someone takens stuff off the tables. HEY GUAR..."
*WHACK*
What made that game especially challanging was there was no quick save feature. When you did a level / area, you had to do it perfectly.
It was a great game. Though I never finished it.