To be honest it would never need to get to that, protected industry action across the board would be easy to achieve if it was a united front under the banner of job and wage security. It just would not get up under one company as per previous point, it would be quite easy to prove to a commissioner that subsidiaries are being used to white ant conditions and that industry wide protection is required in contract set up. This has been done in other industries. It's not hard to get PIA if the company refuses to negotiate a topic, like scope.