Today’s invention is a way for a lecturer to ensure that people don’t all sit at the back of a theatre.
All the flip-up seats are initially locked in the up position (apart from those in the front row).
A sensor mat at the door of the room counts people entering (approximately).
When the number of people inside approaches that of the number of seats in the front row, the second row of seats is released so they too can be flipped down.
The process repeats so that the theatre fills from the front (or in any other pattern the person giving the talk requires).