When American students Angela Luna and Richard Nishizawa tried to board a plane bound for San Francisco in March, airport authorities threw them in a small holding cell and held them incommunicado for several days before banishing them from Japan for five years.

Luna and Nishizawa, who had studied Japanese for a year at Reitaku University, northeast of Tokyo, were not arrested for committing a serious crime. They had merely stayed in the country two weeks longer than their visas permitted.

"We had valid 5-year visas, so we didn't bother to look at our immigration stamps," Luna, 27, said. "The guards made me change my clothes because they had drawstrings. They thought I might use it as a weapon, or strangle someone. We were treated like criminals."