Among many other requirements an employer is required to show they have in place training programs ensuring Australians/Australian employees have or are given the opportunity to be trained or `upskilled'.
Before continuing with unsubstantiated comments go to the Department of Immigration and Border Protection website 457 Visas which is excellent detailing at length all the requirements for both employer and employee.
The requirements which MUST be met are substantial however, employers are not above creating an aura of compliance and adherence attempting to find significant cost savings.
If there a considerable concerns the I strongly suggest you contact then Professionals i.e the AFAP (your representative) who have the expertise and financial resources to deal with this.
Furthermore, the AFAP has dealt with this problem in the past and is currently dealing with and aware of attempts to get around the rules.
Bar oratory and PPrune comments may be highly entertaining however, generally achieve little!
Remember, it is YOUR jobs!