I'm not saying it's impossible to get onto a plane without being checked. Just that ever flight with my partner and family this year, they have been asked for ID. ymmv
This from 2016, and they changed the law in about 2018.
With the rise of domestic airport self-service check-ins, security experts are calling for tougher screening measures for travellers, warning it is too easy for people to move between states undetected.
www.abc.net.au
So yeah, it might be possible to get on a plane without checking ID. But you might also get caught doing something illegal. It's very important to make sure the risks are clearly stated for those reading along at home.