How did the hotel know I was a guest?

Generally, hotels don't care much about this because there are many situations. For example, on holidays, the room is tight, and four people may squeeze into a double room. Or friends come to play and don't leave as soon as they enter the room. As hotel staff, they can't control it. After all, this is a place where you pay for my service. However, at present, almost all hotels have not come up with a special method to realize the contents stipulated by tourists.

In some hotels with strict management system and advanced hardware facilities, there may be a way to do it, that is, the elevator of the hotel can only be lifted and lowered by the room card. When guests check in, the front desk staff will tell them that when they take the elevator, they must use the room card to sense the elevator before they can go to the room. Moreover, guests must report the registered name of the room when they come, and they can call the guests in the room during the day and ask. At night, visitors can only contact the guests themselves.