Canada also doesn't have any sort of outgoing passport control that I've seen. Leaving on a flight, it's possible that the airlines pass your info on to CBSA but there are no controls when leaving by car (you literally drive into the US, then see the CBP) or by boat (you have to report on your way in, but not out, see https://www.cbsa-asfc.gc.ca/travel-voyage/pb-pp-eng.html ).