He flew home to the USA but he was processed in Canada? In other words, did he fly into Canada from SE Asia and then immediately drive to the USA? Honestly, that would look a little suspicious to me if I was a customs officer.
I've flown into L.A. and Dallas/Fort-Worth a bunch of times from the Asia Pacific region of the world and never received a glance at any of my visa pages.
Plenty of international flights connect through Canada, like Vancouver on the west coast. Also, most big Canadian airports have American immigration facilities since they have so much traffic to process, quite efficient actually.
Yes you're on to something. It's kind of a two part story to me:
i) Was it reasonable to suspect this person of being worthy of a closer look? It seems like the answer is a yes based on his locations and pattern
ii) Is the form that that 'closer look' takes reasonable? Causing someone to miss their connecting flight seems unfortunate.
I've flown into L.A. and Dallas/Fort-Worth a bunch of times from the Asia Pacific region of the world and never received a glance at any of my visa pages.