Drpixie, I think you'll find that all those regional operators are still well and truly monitoring area AND ctaf before and after that "switching to ctaf" call is made..
The reason that they make that call is because it is a requirement when landing at a non-VHF receiving aerodrome, straight from the AIP.
I always thought that once that call was made, Centre no longer has to give IFR traffic information on new IFR traffic that calls taxiing?
Regarding 'aircraft 2' - I've noticed that the ATSB swings regularly between naming everyone/everything to operator and what the pilots ate for lunch down to providing type and registration (if even that). Given the media's practice of reading press releases, misunderstanding them and writing silly headlines, I'm not surprised that the operator of 'aircraft 2' asked for or was given 'radio silence'.