Weather delays, duty-time limits....cancelled flight, Captain answerable not SO but....
for SO to stand ground there must have been a serious anomally somewhere that a 3rd pilot should have been easily able to independantly vote the "outlier" out (lucky to have a 3rd pilot).
But too many holes and limited info as always; what FMS inputs, still at gate or on taxiway, LMC, re-route, "interpretation/assesment of runway surface or weather conditions etc etc.
Some inputs and decisions can be interpretive based on experience but as long as the SO was not being @nal for the sake of it (doubt that) then as an active crew member they must challenge.
If not positively resolved in a timely fashion then some doubt probably existed all round the entire crew......"when in doubt there is no doubt", so good job by all not to take an unresolved issue onto the runway.
It seems the weather delays and lack of spare duty time just didn't allow for a timely resolution, leading to a cancelled flight....... otherwise it would have been a non-event (as I'm sure it was) and QF
PR would have one less opportunity to throw distractive mud (blame) at pilots.