Pengilley has neatly summarised the long and ongoing disputation between the Australian Medical Association (AMA) and the Australian Competition and Consumer Commission (ACCC).1 The AMA claims that medical roster arrangements are likely to constitute a breach of the primary boycott provisions of the Trade Practices Act 1974 (Cwlth), a proposition vehemently denied by the ACCC (and by the Wilkinson Committee, which came into being as the result of vocal representations made to the federal government by the AMA).

Pengilley claims to be on the side of the angels (ie, the AMA) with wings; I prefer to be the devil's advocate.

Central to the dispute is to ask what is the meaning of the word "purpose" in any arrangement set out in section 4D(1) of the Trade Practices Act. Is it, as claimed by the ACCC, aimed at — and limited to — an anticompetitive purpose, or, as Pengilley maintains (because the word "purpose" is unqualified), does the section render illegal any roster that has the incidental effect of limiting medical services?

The kind of literal reading of the Trade Practices Act applied by Pengilley had already fallen into disuse by the end of the 16th century. In what is now known as the "Mischief Rule", the Court, in Heydon's Case,2 asked itself "what was the mischief for which the common law did not provide and what has Parliament done to remedy it?". Thus, regarding rosters, the mischief for which the common law did not provide was the "combinations" that resulted in public harm. The incidental effect of section 4D is to give an imprimatur to all medical roster arrangements, save those whose "substantial purpose" is to deprive the community of competition. It follows that the roster arrangements entered into in compliance with the AMA's trade practices compliance program are immune from legal challenge.

Thus, an arrangement whereby Dr X and Dr Y agree on a roster service which may incidentally deprive a community of 24-hour medical cover (eg, because of a medical manpower shortage) is clearly legal, provided no member of the roster deliberately agrees to withhold his or her services. I am puzzled by Pengilley's statement that "Indeed, no roster could function unless Doctor Y agreed not to provide services during the hours during which Doctor X is rostered on duty". Indeed, any attempt by Dr Y to keep himself or herself "out of service" is not only illegal, but unethical, and deliberately "caught" by the Act, and so it ought to be.

In the end, the argument comes down to how many angels can dance on the head of a pin. I am satisfied that Pengilley's argument in support of an amendment to the Trade Practices Act is a counsel of perfection, if only because any attempt by the ACCC to prosecute a bona fide medical roster arrangement would face insurmountable legal and evidentiary hurdles.