https://www.pcpd.org.hk/english/data_privacy_law/code_of_practices/code_data_1.html
Compliance Guide for Data Users - As the Hong Kong Identity Card (ID Card) contains sensitive personal data and the leakage of such data may lead to identity theft and perpetration of fraud. Organisations should be particularly careful when they collect and handle the ID Card data of members of the public.
https://www.pcpd.org.hk/english/data_privacy_law/code_of_practices/files/ID_Leaflet_e.pdf (v2)
https://www.pcpd.org.hk/english/data_privacy_law/code_of_practices/files/picode_en.pdf (v1)
Code of Practice leaflet is to provide advices for listed situations. The indiscriminate collection and improper handling of HKID Card numbers and copies may unduly infringe the privacy of the individuals, and create opportunities for fraud.