[MrDrMcCoy]

There's a difference between tracking attention locally for driving as you suggest, and doing so for advertising and mobile device security, which is what the conversation was previously about.

While I consider your example valid in a vacuum, it poses a substantial privacy and financial risk in the real world. If a car that tracks attention also phones home, your insurance carrier may raise your rates or cancel your plan for occasional glances away (sneezes, children, etc), regardless of an actual problem on the road. Such measures ought to only exist locally within a car, but I have absolutely no faith that it will be implemented that way given the current data shared along those lines.

[fragmede]

I am moving the discussion somewhat but it's not a theoretical. Ford's Blue Cruise system has a camera that looks at the drivers eyes to make sure the driver is watching the road and not texting. It covers a large amount of freeways. it's not as good as Tesla's full self driving but it very much does the job of driving on the freeway in traffic for you.