"We have heard of the terrorist male wearing a niqab and secreting guns underneath. This is a real concern."

No, it's not.

Any coat would conceal a gun as easily as a niqab ... and I don't see coats being prohibited in public places during a Canadian winter.  Coats, and scarves can get caught in an escalator, too.

These are pretend concerns made up by people who don't like muslims.