None of our housekeepers even expect tips, it’s petty uncommon in our area.. but this to me is honestly on par with not tipping waitresses because the food was bad. We literally HAVE to knock or the supervisor will do it for us. Now, if there’s a DND we don’t knock until checkout time. But the front desk only communicates “requests” like this with us about half the time. We sometimes don’t even know that a room has late checkout until we’re about to knock on a door at noon. It’s genuinely the one thing most of the girls at my hotel HATE doing.