A month ago we had a purser on the sfo-syd announcing that you could not buy any duty free onboard and take into Australia. She was confused and should have said that you can't buy duty=free and continue on to Melbourne, but you can buy duty-free onboard and then take onward on Qantas. Cost me the 15% discount that I'd have gotten if I could have bought on board and taken onward to Brisbane.
On another topic, any chance that there is enough business for United to continue one flight on to Brisbane just like the other goes on to Melbourne?