Originally Posted by
YVR Cockroach
Nothing stopping you, it's as if you were denied entry. Maybe let the driver know so they don't wait. Not that there is much there.
I took Amtrak bus on the same route and got off at the border and took a cab to the airport from the Canadian side of the border. Just let the bus driver know that you are leaving so he doesn't stick around waiting for you.
The border guards were extremely friendly, they found me the taxi company phone number and offered to let me use their phone.
I would recommend Amtrak Cascades over the bus though, it takes about the same amount of time but is more scenic, has wifi and I believe you go through customs in Vancouver