neville_nobody;
Removing the flight crew from the country actually stops them being subpoenaed by the authorities. If they were thrown on a plane straight back to Dubai the ATSB would have a hard time actually talking to them if Emirates wanted to play hard ball. If they were in Australia then they would have a legal obligation to talk to the ATSB I would imagine.
This whole thing could become a political minefield as the airline is not a private company as such. So the owners may not be to appreciative of another government authority investigating their company.
Understand and from a political point of view this may make some kind of crude sense but from a flight safety pov, preventing a country's investigative authorities from talking to those involved in an incident or accident within that country is certainly contrary to ICAO Annex 13. Unlike some countries that we have come to know, Australia does not prosecute first and ask questions about flight safety later - at least not the last time I was there, (Dec 08) discussing such issues.