It is relevant to the discussion around mistake fares more generally, and how courts may decide to deal with the issue of mistake when it comes to airlines honouring a fare. It is clear the knowledge of the passengers, and their subsequent actions (or inaction), can determine whether or not they are likely to be successful in forcing the airline to fly them.
My understanding is that australian consumer laws do not currently overrule the concept of mistake.
The SQ case is not as clear cut as there is no assertion that the passengers deliberately 'kept quiet'.
For the Iberia fares in RGN Round 3 the CTA found (my bolding):
The full decision is here:
https://www.otc-cta.gc.ca/eng/ruling/290-c-a-2014
The CTA made the same finding in the majority of other cases against Swiss.
The exception to the above ruling has applied in circumstances where the airline sought to rely solely on its tariff in order to cancel a fare, rather than seeking to void the contract from the outset by virtue of mistake.