Hi BigShip.
Definitely do not think about your son or a friend on a freighter to China.
I personally had serious problem with the Chinese authorities when I landed at PVG jumpseating on "my" airline freighter. The Captain and our Chinese rep. get crazy with immigration officers and finally to convince them to let me "enter" in China, they had to declare that I was travelling as loadmaster without uniform. And note that I was listed in the GenDec and that I have a valid Chinese Visa...