I don't agree that legal action would necessarily take years. An injunction against the removal of ST could have been arranged in weeks. All Unite/BASSA would have to show to obtain an injunction is that they had a reasonable chance of getting the removal of ST overturned in a full Court hearing. That was the approach they tried (ultimately unsuccessfully) over the removal of the crewmember.
In my view, the fact that no application has been made to Court speaks volumes. If I was a striking commuter I would be both extremely worried and absolutely furious with my union for the misrepresentations made regarding the return of ST.