Also, maybe b/c of a market of consumers who don't know what they're buying. I bet tech-savvy Chinese know where to buy safely. But maybe there are a lot of Chinese with poorly educations or orientation to tech, maybe just arrived in a city, or travelling there to shop. And they get stuck by this stuff, and maybe don't even realize it b/c they don't understand the gear, or because so much of it is banged up. (Maybe the camera is also faked.)
It wouldn't surprise me that if a shopowner _was_ eventually caught at this, they'd simply close up and just move somewhere else.
As a free market type, I have to admit that in those circumstances, I don't find this surprising. The "market response" here is for consumers to become more savvy and cautious, but the population posited here wouldn't have resources for that response. And they're forced to choose between wariness, and participation in this new economy with all this neat stuff. And that participation might be the only path out of poverty and ignorance.
It's a crummy choice, and one that is likely to lead to all sorts of bitterness and suspicion of the merchant classes. It founds a similar ethic in the buyers, once they figure out enough to become sellers.
The likeliest defense I can imagine for my free markets is, China isn't really a free market. Its development is artificially stimulated and guided by government policies, which are pushing investments at levels that aren't sustainable, and into projects that probably won't return. A less hyper development might give consumers more opportunity to get up the learning curve, and lower (and probably more realistic) expectations of what they can afford.
Wow, tldr: Govt. accelerated hyper-growth pushes innovation faster than the least informed consumers can manage.