It seems to me that recently I have been confronted by many aggressive housekeepers that appear to want to be tipped for their service. None of them have actually asked me for a tip, but by their behavior and by offering to tell me all they did in my room, it's obvious that they are seeking a tip. I have tipped in the past, but only when a housekeeper did something extraordinary which I thought merited it. But on a normal stay, I don't tip the housekeepers. Unlike waitresses at restaurants, housekeepers' wages don't rely on tips. So is there a protocol for tipping housekeepers? Has this become a norm that I am unaware off?