I can see very clearly, living where I do in Toronto, that there's pressure from certain provinces with the claim that the borders are a cause of infection. I think multiple levels of government find it convenient to toss that football around, but there's no evidence for it.
Evidence of meeting #45 for Health in the 43rd Parliament, 2nd Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was point.
A recording is available from Parliament.