I've had a similar thing happen at a Marriott in Hong Kong.
We'd put out the Do Not Disturb sign overnight after our arrival and the left in out while we we out and about the next day.
I don't recall how long we had the sign out, but at least 24-36 hours.
Somebody for the hotel came to check that everything was OK. They were polite, we assured them everything was fine, and they left.