Stall:
The CASA doc explained the situation of a student who, after a first solo, has a glass of champagne. He then heads out to the aircraft to tie it down or retrieve his navbag. A student in this situation according to the CASA doc is able to be tested.
If this is the case, as you have reported it, then it lowers my respect for CASA even further.
While I am not a lawyer, my understanding is that the laws and regulations are required to be written in a way that a reasonable man can determine from a reading of them exactly how to comply with them, in the sense that it is clear exactly what act results in an offence is being committed.
Furthermore, the enforcement of the law should not be capricious, arbitrary or subject to the whims of the enforcers, because that is how corruption gains a foothold in organisations.
If CASA's answer was indeed that the hypothetical student is subject to testing, then they need to spell out very clearly exactly what the process would be that selects him for testing at such a time and
CASA must then explain and justify exactly how it's organisational objectives are being met by forcing our hypothetical champagne drinking first solo pilot into a procedure involving two weeks of limbo and "assessment".
If they can't do it now, and it sounds like they can't from your statement, they are going to be doing it in front of an appeals court judge or the AAT before too long. I will ask the opinion of two QC's about it at a function next weekend.
If CASA think they are being smart by introducing uncertainty into this process, then they are in for a shock. There is no parallel with drink driving legislation because (a) unlike CASA's regulations, there is little problem with false positives, provided the required time period is allowed after drinking alcohol, and (b) the definition of being in control of a car is well understood, unlike CASA's vague and fuzzy definition of an SSAA.
My guess is that "being airside", or in a building with access to airside, is going to be regarded as too wide a definition of "Safety Sensitive Aviation Activity".