wild goose,
In very broad terms what you've suggested is roughly what happened a couple of years ago. IIRC PIA had been approved but no action announced (under the legislation I think the industrial organisation must give three days notice of, and detail the type of action to be taken), the only action the pilots were taking, if it could be called action, was the wearing of red ties and some made PA announcements.
QF shut down for a day or so, stranded thousands of folk, at a cost said to be circa $200,000,000.
The days of industrial action that you probably recall, are long gone. In some ways this is good, as it takes the bastardry out of things. But it also severely limits employees flexing any muscle.