I don't like government regulation much but there are areas that concern health and safety where government regulation may not be a bad thing.
Making electric cars a bit noisier is one of those areas (Electric Cars Must Make Noises Can Hear Under U.S. Rule). As a runner and walker I have been startled by the noiseless cars a few times. No close calls for me and all my senses including hearing are unencumbered by modern gadgets. Yet I can see how the battery powered cars could pose a danger to people not hearing them or believing they are shut off and parked just before they dart out.
If this saves one life, and I'm sure it will save more, then the cost would absolutely be worth it.