Should a couple handfuls of deaths if as you said you can’t test it any other way? Autopilot systems could already be saving thousands of lives if more widely deployed and a lack of good reliable autopilot systems has the opportunity cost of blood on our hands. Human drivers are well established to be dangerous. Testing and release of autopilot systems should be done as safely as possible, but to think the first decade or so of these systems will be flawless seems unreasonable.