Why did Jiu Hao Hotel stick a yellow symbol?

Make sure the room is safe. Jiu Hao Hotel has a yellow symbol on the door to ensure the privacy and safety of the room during the guests' stay. This is the routine practice of the hotel industry, which meets the industry standards and the needs of guests. Shanghai, referred to as Shanghai for short, is one of the four municipalities directly under the Central Government of China, and it is the economic, financial, trade, shipping and scientific and technological innovation center of China.