The hobie association sailed in Australia for many many years, competing with their state, national, and international titles without any affiliation or connection with the IYRU. In fact they were never allowed to affiliate with the Australian yachting federation because they sailed with full sponsorship emblasoned on their sails and until relatively recent years sponsorship was the "work of the devil" as far as yachting authorities were concerned and any class that embraced it was "outlawed" so although the Hobies are now part of "the establishment" for many years they sailed their "worlds" outside the circles of the IYRU. I think you will find that there is more than one of the "top" (professional) cat sailors competing today started with those Hobie sponsored cats and they haven't as yet been excluded from any international competition by the ISAF.