Are they going to have it playing outside the vehicles? It might be needed as a safety measure. I can speak to this personally because I was almost hit by an electric car (they are being created and test-driven by GM in my neighborhood) walking out of the grocery store because it had started to move when I was out of sight, but heading towards the crosswalk, and I didn't hear it, so I started to cross. It really startled me, and I hope the driver learned something, too. Anyone buying an electric car should have an inservice about the ramifications of engine silence. Any motorcyclist will tell you that a quiet motorcycle is a deadly one, and they have to be extremely careful. You are safer inside a car, but, I'm sure, still not wanting to be involved in accidents. :0)