I'm not sure T-Vasis is all that wrong by saying
Joe Public could not care any less who is driving the bus. They want to get from A - B at the lowest price.
Also I don't think using the PA announcement to get across an industrial relations message is altogether very smart. There's the very real risk in my mind of a backlash from the company and pax. As a pax I would see it as poor form for the bosses equipment and space being used to make a public statement to an audience that has paid to be in that space for reasons other than to listen to that statement. As a pax I would consider the use of the airlines facilities in a situation like this to be cheeky and arrogant thus reducing my sympathy level considerably. A bit akin to using the bosses branded envelopes to post out your CV to prospective employers. Not a good look IMO.
The campaign needs to be, "Aussie jobs kept in Aussie carried by Aussies", making the point that this is only one professional area where this sort of thing is happening or about to happen. Highlight the rumoured FIFO foreign miners and the effect this will have on the average Aussie blokes standard of living.