No, one should not leave their room key in the room. They should carry it with them or let the receptionist keep it for them whenever they are going out. When they check out, they have to hand over the keys to the front office.

While you can physically hand your room key to a room service attendant, it is generally not recommended and is not standard hotel etiquette. The primary responsibility of the room service staff is the delivery and retrieval of food and beverages; they are often not trained or authorized to handle the formal "check-out" process. If you give them your key, it may not reach the front desk promptly, which could lead to delays in closing your account or even erroneous charges if the system thinks you are still in the room. Furthermore, for your own security, it is best to keep your key until you are ready to depart. The most professional way to handle your departure is to leave the key in the room (usually on the desk or a nightstand) and call the front desk to notify them of your checkout, or simply drop it in the "Express Check-out" box in the lobby. In modern hotels, many guests choose to check out via the hotel’s mobile app or the TV in the room, which deactivates the digital key automatically. Leaving your key with a random staff member creates a "chain of custody" issue that is easily avoided by using the official checkout channels.