Proving difficult.
TB – Perhaps this is yet another prime example not of a rubbish regulation, but of subjective interpretation to support a personal whimsy. If you stretch back to Lockhart, the "may require " was translated differently and little, if any 'proving' was done, despite it being an RPT operation. There is a good argument for 'proving' flights; particularly when 'operational control' of tricky over flight clearance, awkward (hostile) alternates and off shore maintenance issues are involved. But there needs to be a cost/ safety benefit justification for the proposed 'junket'; if as you say, the only purpose is to establish that the crew can actually find the desired runway, parking spot, fuel truck and coffee shop in that order proves bugger all.
It's quite right that CASA should examine and test the support infrastructure. The next 'charter' could be to a different location, hopefully to a different one again after that; so do we now need a 'route proving' flight for every charter or simply an infrastructure audit to establish that a robust system of operational support, you know, the type Dom James should have had, exists. For my 30K, I know which I'd rather have.