Steve
Clearly we will need to agree to disagree the Harness Rules are worded a little different from the Gallops which from memory I think uses the term "proper direction", in relation to having to comply that is it must be proper.
Having said that your example about sending the letter to all and then warning some off would not happen because they, that is HRNSW, would not have a prima facie case to ask for the documents in the first place. Therefore it is not proper and would be over at that point.
However, in this case it is a long running investigation to which these licensed persons because of other evidence like the phone records of the stewards involved, have become persons of interest they have been given weeks if not months to comply.
Two people had already been warned off for failure to comply, one was lifted when that person agreed to comply that being "Vallender". Byrnes took his chances at appeal which as I understand it, remains unresolved.
Clearly if it was as you think so unfair the judge would have said to Vallender " mate your sweet do not worry welcome back do not comply" that did not happen or the same to Byrnes.
Michael Siejka is not a green kid, he has many many run ins with officials over the years, he knew the probability of what would happen from looking at those who chose a similar path before him, so at the end of the day he chose his own penalty, do not comply and be warned off or comply and see where the facts left him, I will not speculate as to why he chose the first avenue, I will leave that to others.