Not sure on the new rules, but under the old rules I would say yes.
Forget which reg, but to remain in PRIVATE, the flight cannot be advertised anywhere. Putting it down as a prize constitutes an advertisement, and therefore the flight is Charter (Commercial)
It sucks I know...
There is a work around however. You donate a Gift voucher from an organisation with an AOC permitting charter and its a go....tho the Centre Against Serious Aviation may have buried a new rule to stop you from even doing this. CASA have no room for peoples goodwill
