premise: This highly prized status allows them to live and work in Hong Kong without a work permit.
  Wang warned, however, that China refused to recognise foreign passports held by Hongkongers who had not declared foreign citizenship.
  Millions of Hongkongers have foreign passports, many of them acquired secretly to provide the holder with an escape route if the handover goes wrong.
  Wang said that such passports could not be used for gaining consular protection if the holder ran foul of the law in Hong Kong or mainland China.
  These rules also apply to local residents who hold British passports, he added.
   What may cause the passports to not be used for gaining consular protection?
hypothesis: China refused to recognise foreign passports