This is actually a serious problem in parts of China (Shenzhen, at least). You can never predict what kind of wall outlets will be in a building. Either the UK style (popular in nearby Hong Kong), American style (NEMA 5-15), or Europlug, and sometimes multiple types in one building. At the company I was mostly visiting, each conference room had universal power strips, which accepted all three styles of plugs as well as pinky fingers. I never figured out what the voltage/frequency was, and made sure to plug in only devices that could handle 120-240V.