Originally Posted by
Exec_Plat
...You MAY be also be able to link or have comments added to the award record so they are aware. I know AA will protect travelers even if split tickets, don't know about QF.
My 2 cents
OP is flying UA, so there is no alliance partner airline in Oz to use, and UA has no particular arrangements for their pax. Best to stay overnight in Melb, much nicer tourist city than Sydney and book a cheap ticket for travel a day or 2 later. Money you save will pay for hotel/dinner and a case of wine. This is the downside of flying UA on this route, a lot worse than going with QF or VA, but then it is an award.
It is sometimes possible to get very cheap fares same day even as walkup at the airport, but it isn't convenient and you might have to fly Tiger (an LCC).