They wouldn't be able to do that, Monsieur Dubé, because they wouldn't have the information. Bear in mind that the information that is gathered under Bill C-21 and, as the minister said, page 2 of the passport, is provided by the traveller. So when you go online to check in and provide your passport information, your name, etc., or you're at a kiosk at an airport or at the check-in counter, that's the time when that information becomes available to the airline, not before that.
On October 3rd, 2017. See this statement in context.