Yeah, nah. Not permitted under Australian law. The Labor party did away with that in the late ‘80s.
While you won't get away with it again company by company, a whole industry that jointly decides not to go to work on a day, who's going to fine or launch legal action against 10,000 at once. The walk out rules are only to stifle individual companies from being shut down, there is no way the legal system would cope with or want to cope with an industry wide stop work.
Red light says I must stop, but there is no barrier from me driving right through it. I can then choose not to pay the fine, if I did it on my own, I would suffer the consequences. If the whole of Melbourne decided red lights mean nothing and just did it en-masse the legal system could do nowt to stop it, not enough police to enforce it etc etc.
The recent riots in Melbourne proved all this, 3-5 thousand protesters, a few hundred arrests. Mostly only those that committed violent acts only.
The reason the ATC guys got away with it and AN folk didn't, one controlled the whole workforce, the other was just half of a workforce.
The ideal situation would be a union like ALPA to go global, and we just all jump on board. Then you can coordinate with even foreign hires as well, at least have all these unions work together and not as separate entities.