Another issue that occurs to me is that unless you have citizenship, residence, work permit, immigrant or similar status, Australia only allows, for instance, a visitor from the USA to visit for 90 days as a tourist. If that visitor doesn’t have return transportation booked within the allowed stay, the Australian immigration officers may deny entry put you on the be t flight to your origin. In fact, airline employees in the USA will apply IATA quoted rules and prohibit your boarding the outbound flight.
Use this IAMAT TIMATIC tool
here to determine your admission status to Australia. It is what airline employees use to determine if you’ll be allowed to fly internationally, and it beats us guessing here on FlyerTalk.
Australian immigration is
very by the book, and no airline wants to risk bringing you back on their dime and paying a large fine if you’re denied entry.