Neville, I hear what you're saying, but the Mildura incident is not a good example. Although the two aircraft were carrying extra fuel, neither had planned Mildura as an alternate for Adelaide. The TAF that was valid for their ETAs at Mildura required either 60 minutes holding or another alternate due to a TEMPO period for low cloud.
However even if they had the TEMPO + buffer period at Mildura it still would not have helped them.
Don't agree. Had they been
required to carry Mildura as an alternate for ADL, they would have probably had extra fuel (approach fuel) to go to MEL (Cat 3) or at the least, go back to ADL and do a (shock horror) autoland.