There's an old 4chan post about don't learn chinese/mandarin because you'll be the guy the company sends to china and it'll be on you when the chinese rip off your company. Anon went in to detail about how the samples will be legit and the first few sheets on top of the pile in the shipping container will be legit but the rest will be trash. He said they as a business culture don't feel like they got a good deal unless they have screwed you over.
Someone linked that above, I’d seen part of it before. It sounds like hell.