I know we've already gone over how user ratings are a sad measure of anything and are essentially useless at the moment, but it might be a good idea to make it so that only people who have ratings enabled in their profile can rate others. And along with this, disabling ratings should take a length of time (12 hours, maybe), so that people can't enable their ratings to rate others and then turn it off afterwards.
This obviously doesn't apply if you want to scrap the rating idea, but it's something to think about.
This obviously doesn't apply if you want to scrap the rating idea, but it's something to think about.