You know about this sort of thing, and I am a dunce. In your opinion, could this have been done by accident?
I don't think so...only because there is a finite number of video sources and generally the director can see what is being generated by each video source because each video source has it's own video monitor (little TV). That's why you see the gazillions of little TV screens in the control rooms whenever they put up such a shot. The director needs to see what is coming from each video camera, satellite feed, video tape, the devices that generate the words you see on the bottom of the screen and many other things. It's all up there to be seen, to scrutinize, to be mixed with other video sources and if it looks good... it goes on the air.