I came across a cute song to the tune of "Surry with the Fringe on Top"...
...on this very subject. (It was in this month's Harpers's.) They do have a point.
If the driver is inattentive or the pedestrian steps out suddenly, unaware of the car's silent presence, tragedy beckons.
The suggestion: install a little noise-making device that runs when the car is moving. That would fix everything except careless or drunken pedestrians.