Not a false dilemma, a false assumption. How do you demonstrate the proposition that a car without manual override controls (beyond just a big red stop button) is both individually and systemically safer than one without?
And what driver is going to wait and see if the car is capable of avoiding an accident if they are going to be the ones liable for that accident and told they must take control of the vehicle if they think the car is about to collide with something? Basically you are talking about taking a sophisticated collision avoidance system and short circuiting that by telling the driver they must take control of the vehicle if they think there is a problem. That could demonstrate that autonomous cars are less safe because people will be turning off the collision avoidance system at exactly the wrong times, but yet they will be reacting more slowly than people without autonomous cars because manual drivers are already actively driving.
What California is doing is starting from the assumption that not having a manual override is less safe, which I believe is a false assumption and actually undermines safety efforts. And it could also undermine efforts to roll out these cars.
I am all for the option of manual controls and would probably choose to have manual controls for a car that I owned, but I think that the more compelling case and safer option will be to remove the manual controls and I think the only way you prove that is by allowing the cars to demonstrate the capability.
Many of the most potentially beneficial things that could happen as a result of autonomous cars are those use cases where a driver isn't always at the wheel ready to take immediate control of the vehicle. Car sharing, taxi services, elimination of drunk driving, transportation for the disabled, highway driving at closer spacing which might make a human operator uncomfortable and prone to take control, congested city driving where vehicles could be routed and dispatched more efficiently or just told to "go park and come pick me up in twenty minutes" are all use cases where you don't want to require that someone is 'at the wheel' at all times.
With the real potential for saving lives and helping improve quality of life robot cars should be allowed to prove themselves with and without old school manual controls and all the legal requirements, increased costs and liability that retaining those controls imply.