More from the article...

... The drills by three naval ships happened in international waters beneath a busy commercial flight path over the Tasman Sea on Friday and Saturday, and at least once involved live fire.

There's no suggestion China broke any laws, but analysts say the episode highlights escalating regional tensions over China's influence.

What happened?

The Tasman Sea spans 1,200 miles (2,000 km) between Australia and New Zealand, the largest Western powers in the South Pacific Ocean. Australia's government said Thursday that three Chinese warships were sailing unusually close to its shores on an undeclared mission.

The Chinese military task group were in Australia's exclusive economic zone, the area beyond its territorial waters where a nation has exclusive economic rights. That was "not unprecedented, but unusual," Australian Defense Minister Richard Marles said. ...

@#2

Have any examples of other unannounced live-fire exercises that have caused rerouting of commercial aircraft?

@#4

I note that you did not provide an answer to my simple question of you.