I run into some of the weirdest things. I was taking a class at some conference center, and had to use the restroom. It was a fairly nice place, marble-looking counters for the sinks, automatic faucets, you get the idea. Anyway, after washing and drying my hands, I walked out and instinctively hit the light switch (I'm always after my kids to turn off lights - gotta keep the electric bills down, you know) and was surprised to hear what sounded like someone turning on the water in the sink.
I was fairly certain that no one else had been in there, but since it'd be rather rude to kill the lights on someone while they are still in there, I turned the lights back on and went back to apologize. Surprise, nobody there. But the water had turned off as soon as I turned the lights back on. Curious, I turned off the lights again. Whoosh, all the faucets turned on again. I know, I turned on the little LED flashlight I have clipped to my belt, and all three sinks were running full-bore. Being the considerate person that I am, I notified the building management of the situation left the lights on, and went back to my class.
Stopping in to wash again after lunch, I found a guy working away under the counter. He made some kind of adjustment, flipped the lights off, then back on, tweaked something again, hit the lights, off, on, then came back. One faucet fixed. It no longer turned on when the lights went out. He proceeded to fix the others, explaining when I asked, that they'd been getting horrendous water bills ever since the restrooms had been redone. Until I'd told them, they'd had no idea that the faucets were running all night long when the lights were out. Some quirk of the way the infrared sensors worked allowed them to work just fine as long as the lights were on, but unless they were adjusted just right, as soon as the lights went out, they turned on the water. Crazy, eh?