“Unintended consequences” are outcomes unforeseen by purposeful action, an idea popularised by American sociologist Robert Merton in the twentieth century. Since then, the so-called law of unintended consequences has morphed into a warning: intervening in a complex situation tends to create unanticipated and often undesirable outcomes.

The application of the anti-discrimination provisions of Australia’s Fair Work Act to controversial Australian rugby star, Israel Folau, may be a perfect example of the law in action.

In his notorious outburst on Twitter last week, Folau claimed that a long list of “sinners,” including “homosexuals,” faced hell unless they repented. Folau’s tweet followed similar evangelising on Twitter a year ago, which also caused an outcry then.

Folau is clearly entitled to his views (repugnant as they are). But Rugby Australia should also be entitled to ask him to refrain from expressing them as an agreed term of its player code of conduct (or so you might have thought).

Following the breach of its code of conduct, Rugby Australia announced last Friday: "In the absence of compelling mitigating factors, it is our intention to terminate [Folau’s] contract."

But the Fair Work Act means things are not that straightforward. Folau’s views appear to stem from his religious beliefs. A Pentecostal Christian, Folau believes the views in the Bible are his gospel, including scripture’s instruction to promote the word of God.

The Act’s prohibition on discrimination includes discrimination on the grounds of religious belief. And Folau will almost certainly look to the Act in his defence.

Australian legal commentators suggest Folau may have a good case. If he does, the Act’s anti-discrimination provisions will have the unintended (and ironic) consequence of giving Folau a claim against Rugby Australia for enforcing its code of conduct prohibiting his discriminatory speech. He may even be able to prevent them from sacking him.

In the wake of the 15 March massacre in Christchurch, Justice Minister Andrew Little has called for hastening the review of existing New Zealand statutes that make it an offence to say or publish words that incite discrimination.

As we embark on this conversation about hate speech, we need to heed the perils of unintended consequences. Broad prohibitions on discriminatory conduct might rebound on us, just as they may yet do for Rugby Australia.