Officer was heading towards him. No way he could get the tag (GA does not have a front license plate). Then the officer loses sight of the car (around the turn).
officer turns around and comes back and sees a car that fits the description. If he writes a ticket, he is accusing that particular driver of breaking the law - without any proof. That is a false accusation, since it is unproveable by the officer that this guy was the driver (remember, he was already out of the car).

What the officer should have done is given him a verbal warning. That usually is sufficient to get a person's attention (works on me). What the officer is betting on is that you will just pay the ticket and won't fight it (like most people).
GSP is usually a much more respectable group of cops. Stuff like this is usually pulled at the county level.