We did that to catch whichever cat was peeing on the kitchen counter one time, Sins! We were really upset and tired of it happening, so Rog brought home a studio camera from the station one night, set it up on a tripod, and let 'er roll. Next morning the tape showed all of the cats getting up there, but only one squatting down for a pee! As it turned out, he wasn't really the problem; the problem was the bully-cat, Trystan! Their eyes looked ghostly.:-)