What a waste of taxpayer dollars. How many Prii operating in EV or "stealth" mode have injured or killed pedestrians? It seems to me that the government is trying to legislate solutions to "problems" that are not worthy of its attention. This probably has more to do with lobbyists than anything else.
I am glad that my 2011 LEAF allows me to decide when and where to use the VSP. During late night and early morning hours, I usually turn it OFF before backing out of the driveway. Driving a twisty, one-lane mountain road at low speed with the windows open, I also prefer to turn it off and enjoy the quiet ride. Otherwise, I normally leave it on.
On the 2012 LEAF, there will of course be aftermarket modifications. All I will say is, if you modify your car to disable the VSP and subsequently hit a pedestrian, you will unfortunately be in a weakened position in terms of liability, even if you're not actually violating the law. So watch where you are driving!