回複：請教租車短登加拿大的問題

Don't worry. It is OK to return the rental car in US. Nobody cares.

I landed Canada by driving a rental car thru the border a few years ago. The IO asked me whether the car is a rental car. I said "yes" then he had no further questions. I think the reason he asked the question is because the non-rental cars need to go thru the custom. I came back and returned the car on US side three days later.