Hotel Confusion

Riddle: In a hotel, a man was sleeping when he heard a knock on the door. He shifted the blanket and stepped down from the bed. He walked to the door and opened it to find a stranger standing outside. Upon opening the gate, that stranger said, "Pardon me, I must have made a mistake. I thought this was my room." The stranger then walked the corridor and climbed down the stairs. The man closed the door and immediately called security. He asked them to arrest that stranger immediately. Why did he ask them to arrest that stranger? What made him suspicious?

Answer: The stranger said he thought the room was his. If so, he would have had the key to the room, and thus he would not have knocked.

Source: https://www.riddles.com/11229

In a hotel, a man was sleeping when he heard a knock on the door. He shifted the blanket and stepped down from the bed. He walked to the door and opened it to find a stranger standing outside. Upon opening the gate, that stranger said, "Pardon me, I must have made a mistake. I thought this was my room." The stranger then walked the corridor and climbed down the stairs. The man closed the door and immediately called security. He asked them to arrest that stranger immediately. Why did he ask them to arrest that stranger? What made him suspicious? — Hotel Confusion by ThatOneXavier v1.

Riddle: In a hotel, a man was sleeping when he heard a knock on the door. He shifted the blanket and stepped down from the bed. He walked to the door and opened it to find a stranger standing outside. Upon opening the gate, that stranger said, "Pardon me, I must have made a mistake. I thought this was my room." The stranger then walked the corridor and climbed down the stairs. The man closed the door and immediately called security. He asked them to arrest that stranger immediately. Why did he ask them to arrest that stranger? What made him suspicious? Answer: The stranger said he thought the room was his. If so, he would have had the key to the room, and thus he would not have knocked. — by ThatOneXavier v2.