Originally Posted by
AC681
Flights to the US have to be in paper form, as customs has to stamp it
Originally Posted by
AC681
YUL and YYZ are different, YYZ still requires a stamp on BP
That's the key. YYZ requires the stamp. Get a gate upgrade there, and you board with two BPs.
I did a double take after preclearing in YVR recently, and shouted back "Do you need to stamp my boarding pass?" He looked really confused, and said no.