I recently bought a pair of Taotronics headphones from Amazon. They are a Chinese knockoff of more premium ANC noise cancelling headphones, at a quarter of the price.
The performance is incredible, and if you slapped a Bose brand on it, I could absolutely believe it's the real thing.
I would like to buy more "Taotronics-like" products from "reckless" marketplaces. For example, I'm looking at NASes. The top brand names like Synology are selling ~$40 worth of components BoM for $400. That's ridiculous!
Jeff Bezos is often quoted as 'Your margin is my opportunity'. As a consumer, I LOVE it.
Private sales are different than commercial sales.
I'd argue that any marketplace that allows other commercial sellers on its platform should be held accountable for anything safety and tax related their sellers do.
They should take necessary precautions to verify the sellers and routinely check the products. In Germany VAT dodging by Chinese companies selling on Amazon (let Amazon deliver with FBA and just don't pay taxes afterwards) got recently regulated so that Amazon is liable and the amount of Chinese crap dropped significantly.