Darryl,
I may be completely off base.. As I haven't looked at the AYF rules in a few years..
However calling any title "National" or "Australian" without AYF sanction leaves all who sail in them open to disqualification at any "recognised AYF event". This means any State event (I dont know about club events)..

Back when I last looked at the AYF rules anyone sailing in a nonsanctioned title automatically lost his/her AYF membership..This membership could be regained if they rejoined.. Im not sure about your state but in WA, State and AYF memberships are included in the sailing club fee structure..

I believe the Tiapans are an AYF recognised class and thus hold "recognised" titles.. I can just imagine the happiness all round if someone like Ashby sailed the "National F16 titles" to promote Tiapans and then a few months later, was 6 bullets up in the world A class titles, and gets fingered as a non-member of an affiliated national body.. He may find his non-membership would result in all his results being found void.. Or even if he was sailing later in the Australian Tiapan titles.. Has this happened yes.. I recall vaguely a crew (Tornado?) was scrubbed from a title because they sailed in an "nonsanctioned H16 event"..
It may also pay to review the use of "NSW" or "state" in any event..

This is the reason we had to drop "National" and "Australian" from the Javelin titles..