Though ‘bizarre’, I don’t think the airspace arrangements around Avalon result in HCRPT passengers being exposed to as high a risk as they are at places like Ballina and Mildura. Most of the VFRs transitting the Avalon area, miles from the circuit, will manage to carry and switch on a serviceable transponder, and primary radar will pick up those that don’t.
But don’t worry: CASA has proposed to Airservices that Airservices propose to CASA that the chunk of E at Avalon be removed. Only in the weird and whacky world of Australian aviation....