Is there a new Prius, certain markets, with no off setting on the headlight stalk? It's auto modes only? I seem to recall that, not sure.
I had a 1977 Yamaha RD400 motorcycle with headlights with an on/off switch. Whenever the engine was on, they were on, no matter which way the switch was. And I agree, if your car is moving, the other drivers deserve to be able to see you coming. So I always have my headlights on. (I do set them with 0 second delay, so I know they go off)