It would be a very interesting legal case if the Pilot concerned here refused to cooperate with CASA and took them to the AAT for his medical. Then the person making the reports would have to front up. If they then reneged CASA would be in hot seat as they have cancelled someone's license without any firm evidence medical or otherwise.
What makes you believe that the reporter would need to show up?
The administrative action is by CASA, any appeal through the AAT is between the pilot and CASA only.
There seems to be a few people here who have watched too many courtroom tv shows and movies. In the real world, the rules of evidence are different for a criminal trial, a civil trial and an administrative action.
Creampuff may like to weigh in here.
Put yourself in the shoes of a CASA medical officer for a moment. You receive a letter or phone call telling you that a pilot to whom you have issued a medical certifiacte is a habitual drug user. What do you do? Ignore it?
Of course a process will be followed and it is pretty awful for the person concerned. In my company the stand down would be on full pay, not sure with Tiger, seems to me it may even be personal/sick leave if you do not have a medical certificate.
Is it fair? Of course not but fair is not a word to be used in the modern world really, there is only...is it legal and was the correct process followed.
Best wishes if the guy is innocent.