And even there, once they're in China they can easily go to/be tricked into going to South Korea too, it's just that if they do the South Korean government throws them in solitary, tortures them, forces them to forsake their North Korean citizenship in favor of South Korean, then subjects them to months of indoctrination before they're released, and then they're barred from traveling abroad unless they get in good with some fascist NGO propaganda outfit that'll tour them around the US and Europe.