I remember having a conversation with a former friend a while ago, and he, as a guy who worked for a certain company that makes most of its revenue from delivering ads, spoke about requiring use of front facing camera and using eye tracking technology to ensure you’re actually watching the ads and not going somewhere else while the ads play. If you aren’t looking at the ad, it will play another ad afterwards.
He spoke about it as something he is looking forward to, since it would increase revenue. Pretty sure he was pitching this idea to his boss hoping to get a promotion.