My biggest issue with the 4PM check-out is the FD granting it and then it not being relayed to the Housekeeping team, some of which can be quite aggressive and militant about getting their rooms done. .

I've had them barge right into my room at some properties in the morning, or early afternoon, when I've had a 4pm check-out confirmed by the FD and even sometimes with the DND sign on the door.

Nothing better than being in the middle of some deep REM sleep to have some housekeeper bang on your door, not wait for you to come answer, then barge in screaming "checking out today????" in a high pitched shrill voice as you meet them in your underwear half asleep and startled.

No idea how they can't get the systems to talk to each other!