Help me devise an alarm system for an unbalanced load in washing machine?

I'm afraid my room mates are going to trash my washing machine. I can't trust them to rearrange a load that is so far off balance that it causes the machine to rock and smell hot. It only seems to happen when the load is small and there are 1 or 2 towels. Given enough times trying to rearrange it eventually it will be OK. Can anyone think of some device that will make a loud obnoxious noise when it gets set off by the banging of the washer so they will fix it?