A quick informal survey confirmed my impression that most customers who care to identify sellers and resist going for the cheapest listing typically receive items with no issues (or within the margin of human error), but there does exist a vocal minority who were affected allegedly despite those measures.
If anyone chooses to order memory cards or the like from Amazon US specifically for whatever reason, I find that at least an hour reading reviews and surveying listings is required for me personally to be reasonably hopeful I will get what I want. Trying to spot dishonest reviews or signs that older reviews are for a different product (swapped listing). I imagine if I were in the US I could simply order multiple product variations from different listings & sellers and then pick the most genuine-looking one, returning the rest, but that would be a major hassle when ordering overseas.