Yes, Bleve, that is what we have been saying: that it has become a requirement.
The vast majority of professional pilots operating in/to/from Aus are aware of it so that's why you're hearing it on the airwaves.
But as to whether the "requirement" is really "necessary" - well that's another matter. Perhaps there's an argument that it aids situational awareness of other aircraft out there that might be right behind you? Dunno - any comments?