It depends. If we're talking about somebody who cannot fly because he or she represents a threat to the flight only, but is not a threat to society without a mandate of arrest, then there is no issue; there is no one to be arrested. But if it's a criminal under research or at liberty who is found by the airline ticket agent, of course the RCMP will deal with it with the local police. Transport Canada's role stops at making sure the person doesn't board the aircraft. The rest of it is a police matter.
On March 1st, 2007. See this statement in context.