[interestednovice]

Yes, you are right that PBS in America, especially, and other channels around the world do “buy” access to various BBC News (formerly WN) programming blocks, some of which they transmit live as a simulcast with the BBC’s own output. So the BBC does have to cater to them to uphold it’s contractual commitments.

In the case of Focus on Africa, specifically, though this is no longer quite the case. Previously, Focus on Africa was “slotted in” to the BBC World News schedule and produced and transmitted on BBC WN at the appointed time no matter what. Now, since the merger, it is produced in a different studio to other BBC News programmes, and can theoretically be delivered directly to partners via other ways (a separate feed, etc) so I don’t think it strictly has to go out in the way it used to. Certainly, the UK feed shows something else which other regional feeds could also show too.

It does normally go out on the Africa regional feed, of course.