Having the headlights come on when you unlock it is great in some cases such as in the unlit work car park when it's dark. It means I can unlock it from the other side of the car park and then avoid tripping over the pallets and boxes that are lying around.
It is a real pain in other cases though. Imagine the scene.....a nice, peaceful, serene campsite just after dark and you need something from your car. Unlock it and all of a sudden the campsite is lit up like a football ground on match night
I did find out that if you unlock it the old fashioned way though (with the key) the lights don't come on. Only found that out after a few nights of waking up half the campsite.