There have been many discussions about this, in many online discussion forums.. you might want to check the archives. It was such a hot topic that a few years ago we asked the General Manager of the BoardWalk resort to clarify. He made it clear that housekeepers are not tipped personnel. They're "supposed" to decline tips, but no one polices that, and you won't get anyone in trouble if you leave an extra gift for the housekeepers and they take it. However, you surely shouldn't feel compelled to leave them anything. My personal preference, considering giving a little extra something to folks doing a really hard job in really tough conditions, would be to tip the folks who clean the theme park bathrooms. I wonder if someone could make up envelopes for that for me.