You can pay the fine or spoil your paper. If significant numbers do this, it will be reported publicly.
As it is though, people tend to vote for one of the parties on offer, of which there are many. And as it's also preference voting, Australia is not stuck in the trap of "better vote for A or B will get in" either. You can vote for C, with a fallback to D, E and F before putting in A as a back-stop.
Who knows? The numbers that choose to take this action are pretty small so there’s no particular driver for any political reaction. Turns out if you make people show up, most of them decide they do want to vote.
We also have a lot of choice of parties here which helps. Shame the same 2 majors keep getting in but the smaller parties and independents do take some seats.
As it is though, people tend to vote for one of the parties on offer, of which there are many. And as it's also preference voting, Australia is not stuck in the trap of "better vote for A or B will get in" either. You can vote for C, with a fallback to D, E and F before putting in A as a back-stop.