Slippery Pete,
the point is, when Jooolia thinks there might be damage to the economy, she can stop it all on a whim and there is no accountability for Qantas' actions.
And that's why she didn't use the piece of legislation that Tony Abbott is going on about, because it would have turned into a legal quagmire where her decision had the potential to be legally challenged in court and hence drawn the whole saga out for weeks as opposed to the two days as determined via Fair work.
The piece of legislation that Abbott is talking about is the ultimate piece of legislation should it be required. Perhaps Qantas believed that Gillard would have jumped to this first so as to try and claim some collateral damage to the other pieces of legislation along the way. I'm not sure. But one thing is for sure, the required proof of economic damage was provided for by Qantas managements actions in grounding the fleet, not the unions use of pia.