When a person presents at the Canadian border with their permanent residency papers, coming to be admitted as a permanent resident for the first time, we trust that the paperwork and all the necessary checks have been done by Citizenship and Immigration. It's a very rare case when something isn't right within the paperwork when we would detain or question the individual at the border about the circumstances of their permanent residency.
On March 4th, 2014. See this statement in context.