If SFO-YVR is UA operated, No. None of those flights are Polaris marketed tickets.

If AC operated, there is no definitive posted policy for SFO, however, there is for ORD and the answer is No.
There has been at least one report of a denial for SFO and AC transborder flights.

The reason for the AC denial would be the equivalent UA operated flight would not qualify as a Polaris marketed flight.