Is Victoria under siege from terrorists?, page-25

ASIO have warned of threats from both right wing extremists and Islamist extremists.

https://www.asio.gov.au/director-generals-review.html

Often, those involved will start with violent protesting as seen with the violent Islamist demonstrations in Sydney in 2012 and then progress to more extreme violence.

https://www.abc.net.au/news/2012-09-15/anti-us-protests-hit-sydney/4263372?utm_campaign=news-article-next-actions-panel-2-0&utm_content=link&utm_medium=content_shared&utm_source=abc_news_web

It would not be surprising to see the existing violent anti-vaxx attacks on police, vaccination clinics etc progress to more extreme violence