China is tightening border controls from mid-September and may start searching travelers' phones, a bad sign for anyone from Taiwan or foreign companies doing business there.

• New exit and entry rules take effect September 15, with random checks of phones and other devices expected from October.
• Taiwan's government is preparing official guidance to help travelers protect themselves, and the US has already updated its China travel warning.
• Three groups face the most risk: government workers at any level, religious figures, and people working in chip, quantum, special materials, or defense industries.
• Many foreign companies now hand staff a separate "clean" phone for China trips, showing the worry goes well beyond Taiwan.
• New Chinese laws claim authority over people outside its borders and let the state take over private resources outright rather than just borrow them, which has foreign firms worried about their technology and staff.

Outlook: Expect Taipei to publish travel guidance within weeks, and more companies to treat China trips as a security risk rather than routine business travel.