Agree with Bloggs. No Jet should be going anywhere were un - alerted see and avoid is the norm.
The argument about radio failure/misuse and the incompetence of a pilot is a red herring because it applies to any airspace and amateur/professional alike.
There are a number of issues conflated here in my opinion.
1. Alerted see and avoid isn't perfect. I prefer to call it "radio arranged separation" because, as Bloggs says, the time and window space just isn't there in a jet and the very last thing I want to have to do is rely on seeing a jet in time to avoid.
My personal practice on being alerted to an RPT aircraft approaching is to alter course to remove the possibility of having to spot the jet. For example I will extend my circuit or orbit until I know she is past or landed. This is akin to marine rules - early and obvious action to avoid risk of collision, no matter who thinks they have right of way.
2. The vindictive nature of CASA probably means that very few airprox are reported unless a TCAS RA is recorded.
3. The ADSB solution was stuffed up by ASA/ CASA requiring a $10,000 + GPS source for a VFR aircraft although I believe relaxation is under consideration.