I've been really tempted at times when I see someone who hasn't cleared off their car - at say a gas station, a mall or whatever - to bust out my brush in front of them and clear the car for them...... saying SEE, LOOK - THAT IS HOW YOU SHOULD DO IT.... anything else is a danger to you and everyone around you.
Or leaving a note:
dear driver. I've cleared your car for you. Why?
well obviously you didn't think or take the time to properly clear the vehicle when you should have.
I've cleared your lights, front and back... now we can all see you on the road.
I've cleared your roof, now snow won't end up falling down your windshield blinding you. Or backwards, potentially hitting the vehicle behind you. Now you're no longer a rolling hazard.
Hopefully on the next snowfall you'll keep this top of mind and roll safely!
But I haven't done that yet.