I fly between Canada and USA many times a year and have never had a problem with either the Maple Leaf Lounge in YVR or any RCC in the US I have *G. As for the question is Canada considered and Intl destination from the USA the answer is according to IATA yes it is. However, the Government of Canada has deemed it a domestic flight so they can charge GST. This is the only destination outside of Canada where flyers get stuck paying the GST. What a rip off.
Tax is payable on flights travelling within 500-miles of the Canadian border. If the flight originates in the US more than 500-miles, tax is not payable on the inbound segment, just the return. (We collect taxes to pay for things like universal health care, so thank you for your contribution to our better health standing than found in your own country.) IATA may consider any flight between two countries to be international, but airlines in this part of the world use the term "transborder" when referring to flights between USA and Canada, and USA and Mexico.
At SFO access would not be provided to the SQ lounge since flights to Canada depart from the UA domestic terminal and security will limit access to/from the international terminal.
Originally Posted by
JetAway
If the USA considers Canada "domestic" and if Canada considers the USA "domestic" you have to wonder why we are spending so much money maintaining a border.
Ask your last President. However, as just noted, flights to/from Canada operate from the domestic terminal (US customs/immigraton does pre-clearance at the Canadian airport) and thus check-in is done at the domestic check-in area, not the international one.