Can I stay in a hotel if the lock is not locked?

Can't live. There is a certain risk if the hotel card is not locked. It is useful to lock the door with a hotel card, and the room can only be opened with a key. No need to lock, there is a key card outside to open. It's locked, even if there is a key card outside, it can't be opened. If not, you can find a hotel to change rooms, or find a hotel for maintenance. You cann't buckle it from the outside If you are sure that someone has come in, you can close the door and reach for the stool behind it. Get up in the morning to check the displacement of the stool, and you will know if anyone has come in.