I bet those suits are more of a protection from the polluted water than the dim sum as viewed through China's dirty skies and air. You don't encounter these types of problems in the free land of Taiwan. Oh, and speaking of dim sum -- I think Vietnamese sounds good for dinner this evening.
It's all about keeping white skin b/c somehow the majority of the world believes lighter=more beautiful. They can't go risking being ugly by getting darker!
It's a sign of being wealthy / in the upper class. They associate dark skin with hard labor or being poor / in a lower social class. People spend hundreds of dollars on "skin-whitening" products. If she has to spend any extended period out in the sun, my mother in law (in Seoul) would bring an umbrella to avoid getting tan. It's the opposite here in the states... being tan means you are having fun at the beach or have enough money to go on a vacation.