This was an unprovoked act of aggression. Australia was operating completely within its rights and according to international law. This incident shouldn't deter Australia from continuing to engage in its activities to protect freedom of navigation in and above the South China Sea.
The Australian plane was dangerously near Chinese airspace despite warnings. If Canberra doesn't want to be held responsible for further consequences, it should halt its provocations of China.
The West seems to think that if they put enough military pressure on China in the South China Sea, then China will back down. What they don't seem to realize is that, under Pres. Xi Jinping, the more confrontational the West becomes, the more assertive Beijing will be in response.