I'm curious what the hotel chains' official protocol is on allowing the housekeeping staff to go home after they've finished doing their last room. I know some large hotels have a skeleton cleaning staff working 'round the clock where there is a frequent turnover of rooms, ie. where many airlines house their off-duty flight crews, etc. Someone has to be around to service the rooms where there are late check outs, early check ins, middle of the night plumbing problems, etc. I think all of this plays a role in allowing one a late check out. I personally think a 4 PM late checkout is being more than fair on management's part (and I'm not a "company" man).