My dad visits China, and prefers Canadian customs not to see his many visits to China, as relations between Canada and China aren't great. My dad's flying back from Hong Kong. If he presents his Hong Kong SAR passport in Canada,
will a CBSA officer know that he's a Canadian citizen, notwithstanding his Hong Kong passport? I'm thinking that the computer can match his name and details from his HK passport to his Canadian passport?
If yes to question 1, then will the officer be wary why a Canadian citizen's using a HK passport to enter Canada?
Will there be any other ramifications to my dad? Will my dad be flagged or something?
By the way, https://travel.stackexchange.com/a/37988/35670 claims:
No, a Canadian citizen can use another country's passport to enter Canada. There are no official sources that explicitly disallow it, and empirically, people have done it all the time without encountering any problems.
But this states:
Dual Canadian citizens need a Canadian passport to fly to Canada.
If you are flying to Canada in 10 days and don’t have a valid Canadian passport, apply for a special authorization. If approved, you can board your flight with your valid non-Canadian passport.
In the future, make sure you travel with a valid Canadian passport. Plan ahead and apply soon. It can take time to get a Canadian passport.