Can hotels in Tianjin enter and leave at will?

Yes, you can. Make sure the room in advance, and don't go to the front desk to say that you are looking for someone, otherwise the front desk will ask you to show your ID card and registration number. Anyway, hotels with more than 4 stars are like this, so are those who take responsibility quickly, because there are regulations. However, if you don't say anything, theoretically no one cares. However, the lobby at the front desk of express delivery is usually small. Sometimes they will ask if you are a new tenant and tell them that you have moved in.

Of course, you can live in a single room for two people, and no one will check you and no one will care if you live in 20. It's just a little crowded when sleeping.