That's what those are for! I thought they were just the "[Insert relevant footage]" placeholders that were still remaining at deadline.
This also explains most of 1970s television. In a half-hour programme, you never had Jon Pertwee or Tom Baker suddenly turn to camera and say something like "And now, ladies and gentlemen, here are the Nigel Flatworm Dancers, with their special guest Nancy Twining."
But that _always_ happened on shows that went for the full hour. Thank heavens someone's still looking out for we couch potatoes.