You can't really fault an "operator" of an autonomous vehicle for being on a cellular phone. The operator is there in case something goes wrong...which I'd think an operator would have the common sense and training to know how to drop the phone and take over should something errant happen.
Autonomy is another controversial dilemna. Some people really shouldn't be behind the wheel. Other people, on the other hand, are certainly capable of driving stick, while talking on a cell phone and eating a taco from their lap (me, when I was 17). As long as they don't make autonomy mandated, I'm all for it. I don't really understand it though, since I actually enjoy driving (just not with the ID10Ts on the road). [Before you judge, I started driving in the snow season and have had 0 accidents with 250k+ miles traveled.]
I just think our comforted driving conditions relax people to the point of not really having to learn the fundamentals of driving a vehicle and desensitizes us to the fact that it's a powerful machine at the touch of our fingertips. That combined with insurance and then lawyers that love to give "equal" justice to people that are completely at fault. Take responsibility for your own actions is what I'm getting at.