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?
Do you have to declare your car if you drive across the border?
If you walk over the border, or use another form of transport (plane, bus or taxi), then return in a car. Yes, you’re importing at that point.
No because you brought it over with you. You only declare things you bring back that you didn’t have when you left.
You can do whatever you like, I’m just explaining the rules. Whether you get caught or not is up to how reckless you’re being.