The fact that in most cases the human has to do nothing means that it is unlikely that the human is anywhere close to being as vigilante as an actual human driver. The fact that the human is clueless isn't surprising at all. In fact this is the real danger with systems like Tesla's autopilot. You still ned to be vigilante, but you are so bored that it is hard to be.

The safety humans here might as well be hood ornaments.