That's been the policy for a number of years now. Sometimes they will just knock on the door and stick their head in, sometimes they will come in the room and sort of glance around, sometimes they will empty the trash. Just depends on what employee is doing it. There is no set schedule as to when they will do it and whether or not you are in your room will make no difference. I've had them knock when I've been in the room and I've had them come in the room when I wasn't. I don't even bother putting the room occupied sign out any more but I do always put the safety bar on the door so they can't just walk in if I'm there. 97% of the time if you are in the room, they are very polite about it, there have been stories of people who have asked them to come back later and have been told no or have told them they can't go in the bathroom because someone is in there and they have been told they have to inspect the bathroom. I've never had them do anything but knock on the door and stick their head in, they have never physically come into my room while I was there but that is just my experience.