> In China you're assigned to a city or rural zone and you can't leave that area.

The last time it worked like that was in the 1970s. You can travel and move anywhere you want but you can't legally work, rent a state owned apartment, get social benefits or send you kids to public school unless you get a stamp from the local authorities. It's the same as migrant workers anywhere else.

Of course it's corrupt and unfair and they should stop doing it but "can't leave your area" is a big exaggeration.