It happens to me all the time, I go "about" the speed limit and someone in a truck passes me going 90mph on there cell phone. It drived me nuts, I like the fender mounted gun idea.
I had one guy get behind me in the fast lane. He flashed his lights so I look in the mirror and his hood is flapping up and down with only the safety latch holding it down then I see him lower his coffee cup and he's on the cell phone too.
I wonder if he is the one who crashed into the center divider that day?