I have been screwed a time or two, but honestly, most of the time I've had a pretty good experience dealing with Chinese sellers. Of course that's partly because I choose who I buy from carefully, as yeah there are a lot of scanners out there. I've also been scammed by local people and I think it's important to not immediately judge people based on where they are from.

I'm pretty sure the reason there are so many scammers in china, is because of the amount of poor and desperate people there, and the fact that the situation has been like that for so long, is the reason it seems to have now been ingrained in their culture. There's a huge amount of scammers in other poor countries like india as well.

Edit: typos