Snarek.
You don't seem to understand. This incident was directly caused by a breakdown in the NAS 2b.
"Pilots operating VFR should be aware of airspace where there may be a concentration of aircraft
operating IFR. This is particularly important in proximity to non-towered aerodromes. Remain
vigilant when operating in the vicinity of arrival/departure tracks to runways and navigation aids
Ask an IFR pilot or instructor about areas of high IFR traffic at your aerodrome
AVOID HIGH TRAFFIC AREAS
VFR AIRMANSHIP"
Do you understand the above statement taken word for word from the "Airspace reform - Inflight Guide"?
Your VFR 421 friend was in direct contravention of this advice. He was not only in a high traffic area but he was also approaching, as I have said in previous unanswered posts, a major IFR approach point (Canty) into a major capitol city airport.
Now I may have been able to let this one slip through to the keeper if he was at a lower level, say 5500' or 7500' but this einstein was at FL175, right in amongst the descent profiles of Melbourne bound jets. WHY?