Several past (and some not so long ago world wide) accidents have brought alcohol or drugs into it as a factor.
I can only think of one, the six that in at Hamilton Island 10 or so years ago. What other incidents?
If you're talking about airline flight crew showing up hungover / drunk, yes that has happened but I'm pretty sure it was airport or airline security personnel that caught them out, not the regulator.
CASA loves making us feel "safe" from perceived issues, rather than addressing real issues within aviation.
