It depends. A driver may have seen a child dart behind a car and expect them to emerge on the other side.
Does Waymo have the same object permanence and trajectory prediction (combined) to that of a human?
Once the video evidence it out, it might become evident.
Generally Waymo seems to be a responsible actor so maybe that is the case and this can help demonstrate potential benefits of autonomous vehicles.
Alternatively, if even they can't get this right then it may cast doubts about the maturity of the entire ecosystem