There is a multi-cache in my area that HAD a clue "Was not hidden by a troll." In the area there was a huge stack of cut wood, and of course a small bridge. I thought the clue was an indicator that the cache was NOT at the bridge, and the coordinates were actually leading me more to the wood anyway. After a half hour of unstacking and restacking wood I went and checked the bridge... voila!!! The clue was changed a few months later to not be sarcastic anymore.