Out of curiosity, I just checked Apple’s China web store. They do sell iPhones there, and they do have warranty coverage. I don’t read Chinese so I can’t understand the details. But there’s enough English in the web page for me to figure out the basics.
http://www.apple.com.cn/support/products/iphone.html
You probably don't remember it but about 12 years ago there were some truly great deals on printers manufactured in China ~ they arrived on a ship in Seattle and before anyone realized it all the major computer vendors were selling them.
Alas, they had proprietary design slots for the ink cartridges, and the only place you could get the cartridges was Japan ~ in reality these tens of thousands of printers were not designed for the North American market. Even the brochures inside were in Japanese, and the 15 language instruction booklet was not really adequate to tell you what to do when you ran out of ink cartridges.
Gee, so how'd I know about that one? Well, had my Chinese secretary (who also reads and writes Japanese) translate the brochure for one thing, and then made some calls. BTW, these things had NO warranty! Not here anyway. They offered to send us print cartridges at the very high Japanese domestic price PLUS shipping!
This warranty/warrantless situation is not a laughing matter for customers who get the wrong stuff in the wrong place. Each company has different ways of protecting itself. With Apple it is a common occurrence for visiting Chinese customers to try to buy Apple products in the US ~ for, I'd imagine, the cachet of "look, this one is from America" ~ they really don't care if the things work, and if they don't, they can get them hacked TO WORK back home a lot cheaper than here.