Ixix it is extremely complicated according to CASA . In some cases you would use the nearest CTAF frequency- in other cases you would not!
The FAA has no problems with this as there are no area frequencies . Outrageous I here you shout. Yes they know little about aviation there. They only built the 747 and we built the Nomad.
Creamy. You are of course correct. Hardly any calls as hardly anyone flying.
However it may take only one call for the holes in the cheese to line up and cause an ATC related accident. That's why Pilots are not permitted to make annoucements on ATC separation frequencies in other countries.