To put it into perspective: an upside down American flag is a recognized signal of dire distress which is often meant “extreme danger towards life & property”. Historically, it was only flipped when sailors signalled to allied forces that they were in immediate peril (such as fire, mutiny, or sinking) needing assistance.
Nowadays: both individuals & groups started adopting the inverted flag to mainly express political discontent, dissent, or a deep concern for the direction of the nation. I mean, what happens if you inverted the Australian flag either during demonstrations or if the individual has distrust towards the government?
Not technically, but yes. I believe it’s inherited from US politics (regardless of if the protocol started there or not). Australian government protocols prohibit inverting the flag, even as a signal of distress.
See also, the use of the red ensign by the Australian sovereign citizen cookers - these “freedom”/“patriot” activists are largely derivative of international far-right influences.