Why Does Australia Still Use Fixed-Order Ballots?

> The Bill additionally proposes to remove the requirement to number all candidates on the ballot paper. This is a little more contentious as it introduces new electoral strategies and can impact both positively and negatively on voting outcomes.

I know that it may be impossible to have a voting system which is both strategy-proof and has other desirable properties, but I don't think this limitation requires that the available strategy actually be exploitable (or even findable) in practice by actual voters.

Unfortunately it seems that the mentioned Australian system (despite all its other benefits over FPTP) has exploitable strategies both with and without the complete ordering requirement, which gives a malicious administration one "bit" of control over the algorithm.

Even if they can't predict the magnitude of the effect, they could be tempted to flip that bit based on the direction of the expected change. From the defender's perspective, the fact that the magnitude is not predictable should be even more cause for concern.

The conversion to random-order and the effect on donkey voting would be fascinating. I wonder if somebody has monte-carlo'd it out.