Do hotels use room cards now?

Unless this is a guest house.

There are instructions on the room card.

Aim the end of the room card at the bottom of the door handle and the door will open immediately. Thieves are simple. Turn on the green light, then break the door handle and the door will open. This side cannot be changed. The room card has a strong sensing ability. If not, there will be a waiter on the floor. Just shout, waiter, how to degauss this room card just after it has been swiped? Please show me.

This is more face-saving, and the room card will be used. When you open the room, the waiter will tell you the room card of this room number, which is also written on the card.

The way I said will definitely work. Don't ask the receptionist. Awkward.