Canada does have transit lounges - but Vancouver is a bit odd. They have pre-cleared US immigration, so you have effectively 3 airside zones domestic/US/International.
So if you are coming off/going to a US flight from an international one you have to go out and back in. There is a US <-> International security gate but it's not normally staffed
And screw ups happen - I lost a Lufthansa bottle of champagne they gave me on board for screwing up my seat. At a change in Frankfurt the we had to be bussed from the plane to the terminal - the bus dropped us outside security and I lost the sealed Lufthansa labeled champagne to the security desk.
So if you are coming off/going to a US flight from an international one you have to go out and back in. There is a US <-> International security gate but it's not normally staffed
And screw ups happen - I lost a Lufthansa bottle of champagne they gave me on board for screwing up my seat. At a change in Frankfurt the we had to be bussed from the plane to the terminal - the bus dropped us outside security and I lost the sealed Lufthansa labeled champagne to the security desk.