Human drivers are supposed to be aware enough to learn and determine when and how to engage Autopilot.
Autopilot needs to know for certain, that the Human is aware, engaged, educated and fully capable to keeping within the driving parameters.
Human needs to keep their "eyes on the road and their hands on the wheel". They should be aware that Autopilot is only a drivers aid, and not a driver replacement.
Stupid people have posted themselves sitting in the back seat, reading a book, while Autopilot is keeping their car on the road. Others place attention on their cell phones and endanger themselves and those around them. Many people blame the Autopilot, when it is the Human that is to blame.
Some Humans claim that they are incapable of using their own vehicles in a safe manner. They should not be out on the roads.