I think the whole argument about not having enough Aussies to do the job would go out the window. Their use of the 457 Visa would then come under scrutiny.
They are not 'sponsoring' people anymore; because rumour has it, Australians rejected from the recruitment processes, made themselves aware to the politicians who asked the right questions.
Why are Australians (with ATC licences) being rejected whilst we are simultaneously recruiting non Australians.