Why do you have to knock before entering the room?

This is not only a polite question, but also a rule that must be observed to prevent customers from checking out in their rooms, but the system shows that checking out will lead to embarrassment. The guest lives in the guest room. During this time, the owner of this room is a guest, not a hotel, not a waiter, so you need to knock on the door when you enter someone else's room.

Knock before entering the hotel room. This is a courtesy, and it is the minimum respect for people. It's not good for someone at the front desk to remember wrong.