If he actually flew out of YVR, he was probably in a us preclearance area -- us customs are located in some Canadian airports so flights can go directly into us domestic terminals.
Since those screenings are on Canadian territory, us agents do not have police powers or the right to detain people. They can deny entry but people can leave at any time unless they have violated Canadian law. (https://en.m.wikipedia.org/wiki/United_States_border_preclea...)
If this was the case, he could have simply left the airport at any time.
Since those screenings are on Canadian territory, us agents do not have police powers or the right to detain people. They can deny entry but people can leave at any time unless they have violated Canadian law. (https://en.m.wikipedia.org/wiki/United_States_border_preclea...)
If this was the case, he could have simply left the airport at any time.