Yair. Concentrate on perceived collision risk in vmc rather than real risk in IMC.
Class B everywhere for airlines.
No need for actual ATC vertical CONTROL and Responsibility and an automatic alarm system at places like Tasmania. It will never happen here due to the skill of our pilots not making human errors!
Re usual controller monitoring- I thought in Aus the class D controller was responsible for circuit and surface traffic - not a pilot making an error on a DME arrival.
I suppose time will tell.