Or, God help us, the dude who throws a paper towel into the urinal. What is the logic of this move?

We actually have a sign over the urinals in our rest rooms at work, not to throw paper towels in there. I can only imagine they put up that sign because this was a problem. At work. I don't get it. Not that it is ok to do outside of work, but to me it still seems less likely to happen because there aren't as many random people using the rest room.