alt Hacker NewsDepends what it is. I would trust Nike products from Dick's Sporting Goods physical store and from the Nike store online but not Amazon or any other online retailer. I'd be suspicious of perfume from (say) Giorgi Armani because rip-off artists have heard of it but who would rip off an boutique bland like Phlur?
It probably goes deeper than you expect. A friend of mine unknowingly bought counterfeit Darn Tough socks from Amazon, and only found out when he sent them in for warranty repair. Clough42 has a video on YouTube about identifying counterfeit Mitutoyo calipers (though I believe they came from Ebay rather than Amazon).