I've been on several United Airlines flights recently where the seat backs had touch screen entertainment systems. I swiped my finger over a certain area below

I've been on several United Airlines flights recently where the seat backs had touch screen entertainment systems. I swiped my finger over a certain area below the screen to turn the screen on. Seems like the cameras in the referenced picture might be for the same purpose. Of course, you have to trust the manufacturer and the airline to not use them for nefarious purposes.