"[37] In Legione, Mason and Deane JJ instanced 'fraud, mistake, accident, [and] surprise' as elements which may make it inequitable to insist on termination of a contract for failure to observe its strict terms. Subsequently, in Stern, Mason CJ took Legione and Ciavarella as establishing that the court will not readily relieve against loss of a contract for sale validly rescinded by the vendor for breach of an essential condition; and, in particular, equity was not authorised 'to reshape contractual relations into a form the court thinks more reasonable or fair where subsequent events have rendered one side's situation more favourable'. That latter proposition is at odds with the approach by Gaudron J in Stern, to which reference has been made earlier in these reasons at [35], but, nevertheless, it should be accepted as an accurate statement of the law. ...
[38] ... To the extent that what Mason CJ said in Stern represented a development (or, perhaps, a contraction) of what had been put in the earlier cases, then it is to be preferred.
[39] In Stern, Mason CJ also stated that equity intervenes only where the vendor has, by the vendor's conduct, caused or contributed to a circumstance rendering it unconscionable for the vendor to insist upon its legal rights. That helps explain why mere supervening events and changes in the relevant circumstances are insufficient. But it should be noted that cases falling within the heads of mistake or accident will not necessarily be the result of activity by the vendor. In addition, his Honour spoke in Stern of the circumstances being 'exceptional' to attract equitable intervention. That also emphasised the insufficiency of subsequent events which are adverse to the interests of one side. ..."