Snots in a perspex box

Is it just me, or do most people seem to think that they have stepped into some kind of magic perspex box when they sit into their cars? I don't know how many people I've seen in a car on their own, just sitting there with one finger up their bugle, picking to their hearts content, not a care in the world. Sitting pretty as if we in the car right beside them, albeit going in the other direction, cannot see them! They should bring in penalty points for habits untoward.