If someone tried that on me there'd be a huge problem. It isn't necessary, but there are a few bad people about. I always give as good as I get, but preferably everyone should act with a little decorum.
Just stay away from big people and those with minute brains. Can usually do if there's 2 of you travelling together and if there's 2 of you it can be a little bit intimidating to stuffwits.
My immediate thought was that if airlines installed a device like this it would take potential confrontation (fueled by testosterone levels and egos) out of the equation because no-one could accuse the pax next to them of being a smarta*s^.