We have a very rigorous security screening process at the border. Everyone who crosses our border is subject to very rigorous, comprehensive, and multi-layered security screening. We use biometrics and other databases that we share with our allies, to make sure we have a comprehensive view of who's coming into our country. Anyone who poses a risk to Canadian society is not released into our community. They're immediately detained and put into the removals stream.
On May 31st, 2018. See this statement in context.