Hotel doors have electronic locks. IF you leave after 11am on your day of checkout your key no longer opens the door. They have a pass key that opens all doors.
Happened to me in Mexico. We asked for a late checkout for our room. They said no problem. We got back at 11:30 and the door would not open with our card key.
Yep, you’re right about the electronic locks. I stay at hotels enough and forgot about that.