The troglodytes taking industrial action against Qantas, be is legal or otherwise, are hastening the end of their employment. Nothing, repeat nothing, can justify inflicting hurt, harm etc on an employer's customers. Once bitten twice shy is the attitude of many punters - they have long memories and also know that Qantas staff are some of the better paid members of Australian society and enjoy conditions that many workers would die for.
It's high time that the TWU, ALAEA and AIPA (an unholy alliance if ever there was one) woke up and realised just how fortunate is the collective membership.
(My kevlar vest and full face helmet are on!).