It is a known factor of business in China that they will try and cheat you. We assume in the U.S. that at least people will act according to the moral standard set by our society but this standard doesn't seem to apply to strangers or foreigners in China.

Before you call me jingoistic I have worked and lived in China and they just have a different outlook on "scam" business there.

https://www.youtube.com/watch?v=5ncOyYzOP3w