Originally Posted by andrewwm

I'm not sure on the exact technical requirements for seventh freedom vs. transit differentiation, but United certainly can't sell you any kind of stopover in Canada.

Immigration doesn't generally care about airline requirements on this kind of thing; these types of violations would be taken up against the airline by various airline agencies in international forums (i.e. it is never a violation by you to buy an unlawful ticket, it is only a violation for an airline to sell it to you).