16 out of the current top 100 are currently hatless. Not sure about any of the hiding stackers but I doubt it so let's go with 15% of reward earners are non cowboys. I don't know what percentage of those would be newer users vs limited users vs cheapskates.
Maybe it should be that once you've found a cowboy hat, you only get rewards while wearing one. That way new users don't get punished for not having figured it out yet.