Anytime I see a driver who is doing a crappy job merging onto the highway, or driving 5 miles under the limit and drifting from side to side in the lane, (s)he is on a cellphone. Same with the driver who sits at a protected left turn and doesn’t move forward until the light turns yellow.
Ok. So that’s your focus.
You could therefore join my “faction” against “dangerous drivers” and accomplish even more without singling out cell phones or burgers or dumb kids or old geezers.