What a debacle this whole thing is. +1000 passengers affected. Rebookings. Compensation. Loss of goodwill. Knock on effects. Call center stress. Planes out of position. Downgrades.
There's is only so long Qantas can go blaming the passenger before they need to take accountability and recognise the fragility of their network.
They need to re run their risk assessments and contingency plans again so to avoid repeat situations. Its not like this scenario was a total out the blue unknown.
They are now on borrowed time. If it happens again I don't believe the public will be too forgiving next time.