I always take the leavers that get left behind when someone can't finish a route, usually just a single biner. Kind of like a good booty cam that's almost stuck though. Sort of a Trophy of sorts... and it's even more fun if you know who left the gear, to just give it back, remind them of their short comings ;) Fixed gear is a completely different story. I'm reminded of Potreo, where the first bolts are usually 20-30 feet off the deck because if you put them any lower then kids will steal the hangars and sell them for scrap.