I mean, say, you want a really camera, or a drone, and since those things are made in China, they are too expensive to buy. 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?
The ones that do it for family and friends get away with it, the ones that get peppy and decide to start flogging groceries, etc on Fb Marketplace get watched. It’s really not something you want to try to profit from!!
Like many things they won’t bother for occasional personal use, but will come down with the hammer if it turns into a business.