So far at the London Olympics, seven athletes from Cameroon went missing, and three from Sudan have requested asylum. The Olympics have been the scene of political defectors, asylum-seekers, and others who don't want to go home ever since 1948, when the president of the International Gymnastics Federation took the opportunity to avoid returning to Czechoslovakia.
Marie Provaznikova, a Czech who was President of the International Gymnastics Federation, was the first person to defect from the Olympics. Czechoslovakia had recently become a satellite of the Soviet Union, and Provaznikova knew her country wouldn’t be the same. She darted to the United States, where she later taught gymnastics. Provaznikova lived in the U.S. until 1991, dying at age 101.
Read the stories of defectors from many different Olympiads at mental_floss. Link