GPS-enforced speed could be done fully internal to the vehicle. THe jurisdiction data would have to be accurately stored internally, but that’s not incredibly difficult; e.g. Apple Maps has speed limit info for something north of 90% of US roads.
True. But they can do that with red-light cameras to where only the offenders data is captured. I think the issue is more on how they will implement the system than how they could implement the system. I can't see them setting up GPS enforced speed and not wanting the ability to track the location because of theft/national security/[insert favorite soapbox].