Dame Sian, who was a lawyer for the Maori Council in that case, must have thought long and hard this time about imposing a similar order on John Key before sanctioning the transfer of Mighty River Power from the State-Owned Enterprises Act to the new law governing his "mixed ownership model".
That she did not - or was talked out of it by fellow judges John McGrath, William Young, Robert Chambers and Susan Glazebrook - says a great deal for the social and political climate in the country.
Their unanimous decision did not need to refer as far back as 1987 for a comparison. The reaction of the public and the previous Government to the foreshore and seabed decision will still be in their minds.
The judgment so deeply disturbed our understanding of rightful public property and democratic power that Don Brash nearly got elected. But when we all settled down, Maori had a new political party, National had a younger leader and together the parties were able to resolve the foreshore and seabed without much rancour.
More than that, their governing alliance has created the "social environment" that has given the Supreme Court such confidence that the freshwater claim will be resolved.
Under their pact in 2008, the Maori Party also got the Government to agree to a public exercise designed to bring our constitutional consciousness out of courtrooms and into the general conversation. A well-chosen panel of worthy citizens, Maori and Pakeha, launched the exercise this week.
I'm not sure it is possible to have an orderly, civilised conversation about a constitution. Most of us don't worry about the system of government until it is in some sort of crisis, when the conversation is more of a convulsion.
Had the Supreme Court's decision this week been different, we might be having just such a convulsion now.
Many - me among them - would have been complaining that if a government had no right to sell shares in a company it owned, what has happened to the rights of government under the Treaty.
That was also the view of High Court justice Ronald Young when he dismissed the Maori Council's challenge last year. The Supreme Court says he was wrong. And it bases that view on legislation, as courts must. Under our Westminster constitution, Parliament is supreme.
This time last year, the Maori Party put its pact with National on the line over a clause in the State-Owned Enterprises Act called Section 9. In essence, it said companies constituted under that act had to comply with the Treaty of Waitangi.
That little section, a legacy of Sir Geoffrey Palmer, brought the Treaty into law and was the basis for Sir Robin Cooke's 1987 declarations. Last year the Maori Party succeeded in getting an equivalent clause written into legislation for National's "mixed ownership model".
This week, the Supreme Court said it would have meant the asset sales were not "Treaty compliant" but for the Government's undertaking now to consider the case for iwi control of water flowing through their ancestral territory.
The citizen panel and its opponents are likely to waste a long conversation on whether the Treaty can or should be at the heart of our constitution. It is.