Fair Work; Adverse action against employees

There is an extraordinary provision in the Fair Work Act. It is section 361. The practical effect of the law is that if an employee brings proceedings against an employer for contravening the prohibition against taking adverse action against the employee for exercising or having a workplace right, or discriminating against the employee on any of the specified grounds, or dismissing an employee because he or she is temporarily absent from work due to certain illnesses or injuries, then once the allegation is made, it is presumed (yes, believe it or not) that the action was taken for the prohibited reason, unless the employer proves otherwise.
It is true that the original Rudd government (through then Industrial Relations Minister Gillard) argued that this was perfectly reasonable because the reverse onus also applied to unions which might be alleged to have broken these laws, but the reality is that the real effect of the amazing provisions is to render it necessary for employers to prove that their actions have been lawful when they are under scrutiny in this context of the Fair Work Act.
How does an employer prove that it did not have an intention?
Consequently, how an employer might reasonably go about proving a negative is an interesting topic in itself.