Originally Posted by DWB

Not that easy. You can't stop the Africans from leaving Africa via other means, like on land, and into Europe, then they can go anywhere. People are trafficked, people cross borders illegally, and so on.

Africans are POURING out of Africa currently, going all over the world, especially Europe and Asia. Once there, they can hop a plane to go anywhere else.

You must stop Africans, not just travel to/from Africa. Even then, that isn't a sure thing. But it will help. Though, it is an impossible task unless they want to build a giant wall (think Escape From New York) to keep them in the continent.