Earlier quoted context omitted.
It also would prevent government agencies from demanding i.e. the source code of a car's ECU to verify its safety and emissions behavior. The only way out of this would be to declare car ECUs (or other systems) as "critical infrastructure", the definition of which I'm sure will be subject to many political tug-of-wars once this is implemented.
Playing the devil's advocate here, but you shouldn't need access to a car's source code to measure its emissions. The test is broken, not the software.
It's like weighing someone, you don't need to see their feet, but if you can't then you can't tell if they have both feet on the scale.