Have they not heard of take it out of gear and turn the ignition off ?????? Then slowly drift to a stop on the brakes, yes you will have no assistance on the brakes but they will work you just press the pedal a bit harder.
Although the car in question will automatically slow down to about 20mph and turn off the auto cruise when you open the car door and takeoff your seatbelt, so there should have been zero issue and danger to anyone, perhaps some of these people should actually read the handbooks given with their cars.
All good points but I think there is a phenomenon that occurs when you tell a human that his/her car has autonomous features, even basic ones. That is, after a while, the human begins to trust the autonomous features and tunes out, creating really slow reaction times (even assuming they read the handbook!).
I have pointed this out on numerous occasions but this is something that Google/Waymo discovered a number of years ago when they were testing AVs with their employees in the driver seat. This is the main reason that Google skipped entirely the concept of depending on human input behind the wheel and going straight to Level 5 autonomy as their desired goal.
By the way, on your input previously about human safety drivers looking at screens showing the cars performance rather than possibly at their mobile devices (something any reasonable human would be inclined to do after hours of tedious, boring screen staring), are your human safety drivers specifically prohibited from carrying their mobile devices into the vehicle while they are testing?