Was interviewed on the bridge off a FRA-YYZ flight a few years back. Possibly random, possibly targeted I have no idea (one-way ticket bought an hour before take-off and no checked luggage). Toughest interview ever, most questions intended to provoke hesitation or worse, answers didn't seem to matter, except for company I was visiting closed and not having after-hours number to confirm.

At some point I mention connection to Montreal. Interview stops on the spot, passport returned, 4 agents (yes 4, 3 watching 1 talking) suddenly uninterested, free to go. Montreal is a magic word (maybe). Try it if need be!