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?
As I and others have mentioned elsewhere, you’re taking a risk doing this, as if you get caught it will cost you more.
One other thing to keep in mind is warranties if anything goes wrong with the item. If you are trying to make it look like you brought the item with you, you’ll be getting rid of all the documentation and packaging that proves you purchased it. That includes receipts. Warranties often require proof of purchase, so you may be throwing away your warranty by doing this.
Also, keep in mind that models and model numbers are often different in Canada. I’ve had phones that were identical to the US model but had a different model number. I’ve also had phones where they sold the European version in Canada (again with its own model number) and so it was basically a different phone from what you’d get in the States for the same model name (different CPU, different supported communication protocols.)
Often our model numbers will get a “CA” added to the end making it obvious. Sometimes it won’t be obvious, but won’t match model numbers you can easily find info for online. My current laptop model number is undiscoverable online because it is so rare. There are similar ones for which the info mostly matches my computer, but I’m not always able to find good info.
It’s kind of funny watching Americans talk about this now as it was something we Canadians used to talk about all the time… Strategies for buying goods in the US to save money.