I refuse to believe that's true. That they were denying Dorothy (92) from going through customs because she couldn't use an app. That's an extraordinary claim.
If they weren't denying Dorothy, that means you did not need an app.
It was compulsory during COVID and it became optional later
https://en.wikipedia.org/wiki/ArriveCAN
It was compulsory during COVID and it became optional later
https://en.wikipedia.org/wiki/ArriveCAN