NO, I don't, and I actually called my daughter, whose house I had just left...but if I had, I wouldn't have cared...
She wanted me to get his license #, but I told her I didn't want to get close enough behind him, because the way he was acting, and with all of the traffic, I was afraid he would stomp on his brakes, and I would end up crashing into his rear end, and then get rear-ended myself...
I do know that I was not going to go much further W/O actually calling the police....when he saw me show him the cellphone, he hit the very next exit....whew!
I think you were wise to not prolong the incident any further than it needed to be. You are correct, if you had dropped in behind him, he could have done just what you feared. And then the cops would likely give you the ticket for rear-ending the perp.