It's not, unless you have an exemption (compassionate or whatever)...

In this case, I believe he jumped the border and was then caught. Which... These are state borders, here. They should NEVER have been allowed to be closed. And it also implies, I suppose, that someone dobbed him in...

Re your second question, that really depend on how rich and powerful you are, and who you know...

If you're Zac Efron, or mining magnate Twiggy Forrest, or Chris Hemsworth, or a politician, you can come and go as you please, and you WON'T be subjected to this hotel prison situation...

For you, or I, or anyone else, like in this video? No, we cannot leave (even if you normally reside overseas, as of last month), and the waitlist to enter has some 40,000 people on it, has done for six months, and the wait time keeps blowing out, month after month, as Vic and NSW, for example, put interstate travellers (as here), in the hotels instead...

Alternatively, you may end up in a literal quarantine "camp", like Howard Springs, in Darwin. 35 degree heat, and 100% humidity.

You can go outside, there, but the cops are even more oppressive, and heavy-handed, and I fully expect they would be happy to kill, or at least permanently maim you, if you cause a fuss, as here...

So really, not much better. They're building more camps like that, too. And yes, Godwin's law, but you... Get that this isn't a great look. They plan to send us unvaccinated, there, in future, too...

Does that sort of answer your questions?