I'd be a rich man if f I had a dollar for every time housekeeping ignored the "do not disturb" sign and walked in on me on check-out day, with or without late check-out due to elite status.

Of course you make a fair point about considering others, but I rarely see any restraint at all in "determining whether it's vacant" and many hotels have a drop-the-key express check-out box which informs nobody at all about your departure.