Another anecdotal point, in the past few years I've entered the US a dozen times, China, SA, Australia, Canada and some European countries outside my native France, and I've never been asked to unlock my phone once. I always get the fingerprint treatment at LAX though.
Getting fingerprint is supposed to be a standard procedure.
I was asked to unlock my phone trying to get to Canada as a US citizen too.
What are they even trying to find on your phone?
Evidence that you're coming to Canada to stay and perhaps work, rather than visit temporarily.
Interesting. When they ask my occupation I say that I’m a small business owner in the software industry. Is that a high risk occupation for unauthorized work in Canada?