At Tsinghua University, students are said to spend more on bike locks than on bikes. A friend of mine, a senior, is on her fourth bike. I met a faculty member who went to get her bike just as it was being stolen. She saw how it was done: The thief had a large number of keys. She shouted at the thief to stop, a crowd gathered, and he gave the bike back. Later she encountered him while buying pork: He was the butcher.