This shouldn't be too hard. Have a few friends order a "product" you never ship or even pay a few people on Fivver to do the same. Costs $25 tops. Hell, you can ship them an empty envelope to put some tracking on it.
If I were the scamming type (and I'm not in the least) I think a decent scam would be create a really good quality private label product. Sell for six months at a very small profit margin. After the good reviews and best seller rankings pour in replace the inventory with shitty quality product at a huge profit margin. It would take a long time for the sales to stop. The initial sales inertia would take some time to slow down.
Maybe that wouldn't work, who knows.
The one thing Amazon has generally been really good with is customer service, and easy returns/refunds.
I'm not actually sure what the scam is. Does the seller disappear with Amazon's money? Or earns interest? Or maybe they speculatively list many lines and only manage to source a few?
Here are a couple of such sellers (I suspect in fact the same seller appearing twice). I was conned by both when ordering some bicycle parts, despite checking their feedback very carefully at the time of the order. I still haven't had a refund from the second one.
https://www.amazon.co.uk/gp/aag/main?ie=UTF8&asin=&isAmazonF...
https://www.amazon.co.uk/gp/aag/main?ie=UTF8&asin=&isAmazonF...