Depends on what it is. Years ago, as I was stepping off the boat, exiting the ride at Pirates, I had my video camera and my back pack slung over one shoulder. Somehow the back pack pressed up against the video camera and hit the release button for the video camera battery. Right as I stepped off, the battery unlatched and fell into the water. I heard the splash, looked down, and had no battery on my camera.
I probably couldn't have dropped the battery between that small space between the edge of the boat and the edge of the loading platform if I had tried! I looked up at the CM, as he saw it happen. He said, "sorry about that." I said, "guess I'll never see that again, huh?" He said, "well, every year or so we drain the water, and you'd be really shocked at all the stuff we find. But I doubt it will be any good after being in the water that long."
The most annoying thing was I had JUST bought that battery for the trip, so I'd have an extra one, and it was the FIRST DAY I had used it! And those batteries were EXPENSIVE back in the early 90's!