I flew YHZ-YYT on Sunday; upon arrival at YYT, they ("police cadets" on the back of their tshirts with a full uniformed police officer overseeing) were handing out forms to complete and you had to show two pieces of ID to prove you were a resident of Atlantic Canada. While the flight was wholly within the Atlantic Canadian bubble, I guess people could have connected to YHZ from outside the bubble and still have been on that flight, say YUL-YHZ-YYT. They were quite efficient and polite; the form is also available online to print out if you don't want to spend the additional couple minutes filling it out upon landing.