A real life for-example:
There's a specific kind of cat treat I used to buy on Amazon, at some point various (or maybe the same under different names, who knows) resellers began to sell that treat in a way where they would break up the retail packaging and sell single pouches for the same price as the MSRP for a whole case (the way the manufacturer sells it).
Technically not exactly fraud because they mention the size in the item description fine print, but because of the pricing and the way Amazon tends to just mix different SKUs from both themselves and resellers willy-nilly into different options of the same listing, its incredibly easy to just assume you are buying the full retail product as packaged by the manufacturer.
To Amazon's somewhat-credit, they've refunded me when this situation occurred, but to their shame they've never done a single visible thing to stop this practice from happening and I've proactively reported it to them repeatedly.
End result is there's a whole bunch of categories of products I won't buy from Amazon anymore because I don't want to have to do in-depth detective work every time I make a purchase. I get my pet stuff from Chewy now as I've yet to run into a similar scam on that website.