A Taiwanese business traveler was held and interrogated at Shanghai's airport simply because he once worked a low-level job at Amnesty International — a warning sign for anyone from Taiwan traveling to China.

• He was stopped at passport control on arrival, labeled a political case, and taken to a back room for six hours.
• Three plainclothes officers pressed him to unlock his phone, then went through his messages, email, and photos.
• They demanded to know where the group's money came from, who he knew in Taiwan, and whether he came to meet sensitive contacts.
• He was let go only after giving up on entering the country, and flew back to Taiwan the same night.
• Chinese authorities appear to hold full staff lists for human rights groups, and airport systems including Hong Kong's are linked together.

Outlook: Expect more warnings against travel to China for Taiwanese with any NGO or rights-group history, and fresh questions about how those employee lists reached Beijing.