How do automated systems deal with flaggers? Visibility of the stop/slow sign isn't sufficient to make a determination on whether it's safe to proceed (not to mention "stop" changes meaning here, entirely, from a typical stop sign). Often, whether or not you can proceed comes down to hand gestures from the flagger proper.
Not that I expect any reasonable driver to be using something like autopilot through such a situation, but we've also seen plenty of evidence that there are unreasonable drivers currently using these systems, as well.
Of course, the problem is, if we haven't developed it today, the ADAS systems of today won't understand it in ten years when there's enough saturation to be practical to use it. Apart from Tesla, very few car manufacturers are reckless enough to send OTA updates that can impact driving behavior.
Lane-following ADAS systems of today, mind you, can work relatively fine in construction areas... provided lane lines are moved, as opposed to relying solely on traffic cones.
However, I also once so far have experienced what happens when this system experiences a poorly-marked construction zone. Whilst most construction sites on the interstate system place temporary road lines for lane shifts, this one solely used cones. While I was paying attention and never left the flow of traffic, the car actually fought a little bit against me following the cones into another lane, because it didn't see the cones, it was following the lines.
It doesn't surprise me at all that if someone gets too comfortable trusting the car to do the work, even if they think they're paying attention, they could get driven off the roadway.