This is a general rule for star-rated hotels! There is a reason why the service staff should wear a uniform black color! Because the waiter then work harder, catering waiter is even more so. Every day with the meal to deal with, it is easy to get dirty uniforms and shoes and socks. Therefore, black is more resistant to dirt and less visible, of course, the uniform is to be changed every day! If you wear white socks, they will get dirty easily, and it will be unsightly for the guests to see them. This is also the international practice of the hotel industry.