A simple factual report is all that is needed.
Is that actually going to come from someone who was driving past at the time?
The whole opening post / thread is operating under an assumption that the Pilot in Command isn't going to bother to report this... guilty until proven innocent. It would take a brave man to not report this at the risk of his licence, fines, jail, not to mention issues with his insurance company.
What's gained if he is right- everything, most probably at the cost of some more training....
More training? It would be a moderately rare occurence for the ATSB or CASA to request more training for such an event.
It seems that there would be little to be gained by a third-party to report this kind of incident.
I know of an incident where a third-party reported it and got the rego wrong which left an innocent party to defend themselves to prove that they were not involved. The reporter simply needed to p
ss off and butt out!
which is what most of us think should happen here!