Luckily china has a litany of 3rd world countries land borders surrounding it with porous borders, and in a great deal of them no one who gives too many shits about some poor chinese villager crossing. Americans on the other hand have Canada which for LEO purposes is basically an extension of the US, and Mexico which due to the drug trade and other unique factors mean anyone getting caught jumping the border in either direction is likely to owe the cartel a massive amount of money or some extremely undesirable favors.

I would definitely rather be a trapped Chinese trying to escape than a trapped American.