I've had check out times as early as 9:30 am in full service hotels that were part of a conference center. My worst experience with this was returning from breakfast at about 8:30 am to find a housekeeper in my room (ignoring the do not disturb sign) starting to do something to the room despite the fact that I obviously had not checked out. She had rearranged the items that I had been organizing to pack, so of course it took me longer to leave than it would have is the staff had just stayed out. Very frustrating.