I'd say report it and make sure that a report is filed. We had a doctor over here in LA that had the habit of swooping in front of cyclists and than break checking them, i.e. slamming on his brakes forcing them to do the same to avoid colliding with him.
The last time that he did this it was against two cyclists who were (if I remember correctly) finishing up with an organized ride. Their only real "crime" was that they were riding two abreast on "his road" as well as they were traveling at the posted speed limit at the time.
One of the cyclists got some serious road rash, the second crashed through the rear window almost cutting his nose off as well as loosing several of his teeth. The good doctor than called 911 and stated to the 911 operator that he wanted to teach the cyclists a "lesson." Because he had done the same thing to several other cyclists there was a paper trail that eventually lead to his conviction, and he is now warming a jail cell.
