Taiwan is warning its own citizens that China's revised exit and entry rules, in force from Sept 15, could be used against Taiwanese people who travel to or transit through China — bad news for anyone with business, family, or work ties across the strait.

• The rewritten rules give Chinese authorities broader grounds to stop, question, detain, or bar people at the border.
• National Security Council advisor Huang Chung-yen flags three high-risk groups: Taiwanese who work or run businesses in China, people active in politics or outspoken online, and those holding Chinese ID or residence documents.
• The worry is that the rules are written loosely enough to be applied case by case, so the line between legal and illegal is whatever Beijing decides.
• Taipei reads this as part of a wider squeeze — legal tools used to pressure Taiwanese citizens rather than the government directly.

Outlook: Expect Taiwan to push more travel warnings and for cross-strait business travel to get more cautious after the rules kick in.