I mean, say, you want a really nice camera, or a drone, or maybe a gaming laptop, and since those things are made in China, they are too expensive to buy right now in the US, since tariffs are over 100%. So you just go to Canada, buy the thing, unpack it from the packaging, and pretend like its just personal items. Just like a smartphone.
AFIAK, border agents usually don’t ask if you bought your phone in the US or from outside, they shouldn’t ask about other personal electronics, right?
You are wrong. North America is a continent, and South America is a continent. Of all the countries on these two continents, one is colloquially referred to as “America” by everyone who isn’t an internet weirdo. Absolutely nobody else in the western hemisphere refers to themselves as “America” or “Americans”
Yes, I am aware that this is the prevalent misconception in the USA. If you spoke more than one language you’d quickly realise this is not the case in the rest of the world. For example, your demonym in Spanish is Estadounidense, which means Unitedstatesian. In German it is US-Amerikaner, the meaning of which you can probably understand. The demonyms are such because they understand that the USA are a subset of America.