For all the backlash at the slow response by Australian authorities, it is interesting to see the wording of cruise line health policies. Australian protocols were "owned" by health officials, not politicians and it is interesting how closely they aligned to what the cruise lines still recommend.
Carnival Australia:
Vaccines - Although vaccines are not required, we encourage all guests, 5 years of age and older, to be up to date with their COVID-19 vaccines, when eligible, and carry proof of vaccination,
Testing - Will test anyone in the terminal that is displaying symptoms, and deny boarding to anyone testing positive,
Masks - Masks are not required on board during your cruise. However, we recommend guests wear masks in public indoor spaces, outdoors when in large congregate events if they’re feeling unwell or exhibiting symptoms of illness.
Isolation - Any guests exhibiting symptoms of illness are encouraged to go to our medical centre. Guests who are diagnosed with contagious illnesses may be required to move to an isolation stateroom until our medical team determines if it is safe to resume cruise activities.
Still recommending what used to be enforced - maybe AHPPC was on point.