Why is this relevant?
This is a sad accident where people are killed. Its no more or less tragic that they were under the auspice of Angel flight, or scouts, or the local school or next door neighbors of the pilot or some flying mates from his local airport.
The CPL licence is designed to teach pilots how to operate under the operation manual of a commercial organisation and fuel and navigation planning in environments where the commercial nature requires a pilot to operate with less discretion to add personal safety margins.
Speaking as a CPL, as much as we might like to think that we are demi-gods, the CPL licence does not mean that we fly any better or more safely than a PPL. And if there were something in the CPL syllabus that created safer pilots for flights like this, then CASA is culpable for not implementing in in the PPL syllabus.
I might also remind you that only a week or two earlier in nearby Renmark were there also 3 fatalities. Except that there were 2 highly qualified CPL's and a CASA examiner on board.