[throw_m239339]

> Can't North Koreans freely travel to and from China?

Of course not, NK is an open air prison for its nationals.

[erichocean]

Yup, China literally built a wall to prevent North Koreans from entering China.

[pastacacioepepe]

Many thousands of north koreans still work abroad every year. Hard to keep an entire population completely isolated from the world when you have thousands constantly travelling abroad.