No need for angst' Squawk! Easy or not REX have jumped through the hoops (as flawed as they are), and unfortunately they are not alone.
Back in '07/'08 REX management, aided by a still politically influential board member, garnered substantial government support WRT employing foriegn pilots. The result at the time was modest (5 South Africans), but in many respects the die had been cast. As far as the union effectively opposing this practice, I think you fail to realise just how difficult this may be. That's not to say it isn't worth a shot, but lobbying aside, any sort of industrial campaign would more than likely backfire, given the number of appendages in certain pockets.
Personally, I think it may blow up in REX's face anyway. They'll pull out all stops in the inevitable efforts to save face, but the fact remains they have neither the will nor the whereforall to effectively manage their crewing issues into the future.
The most we can do at this stage is sit back, and enjoy the show. and remember Squawk', we're all on the same team!