The decision at issue was quashed as substantively unreasonable. From the following extract, it is easy to see why:
 Any reviewing court upholding a decision whose bases cannot be discerned would blindly accept the decision, abdicating its responsibility to ensure that it is consistent with the rule of law. In this case, the decision letter, signed by Ms. McManus, merely asserts the exemptions that apply. No further reasons are given. The record consists of a relatively thin affidavit, documents that have been produced to the appellant, and documents that have been withheld from the appellant. This material does not provide us with the basic information we need in order to discharge our role...
From the perspective of any administrative decision-maker, isn't the import of this sort of decision that it is better to provide coherent reasons to survive substantive judicial review? From the perspective of the individual affected by an administrative decision, isn't it quite unimportant whether this is a matter of procedural review or substantive review? These deficiencies in the information provided to the Federal Court rendered it impossible for the Federal Court or this Court to carry out their respective roles. In this case, the Crown vigorously maintained that there was no reviewable error in the decisions. This may be so, but this Court cannot decide the matter. In the circumstances of this case explained above, with such little information in the reasons and the record, that is equivalent to an assertion that this Court should just accept the decisions, not test them. In effect, the Crown’s submission is “trust us, we got it right.” Acceptance of that submission is inconsistent with our role on judicial review.
What counts, surely, is that the decision-maker has been forced to justify its position in a coherent and intelligible way. This is what the Court was driving at in Newfoundland Nurses, I think. With progeny like this, it is hard to argue with the thrust of the Court's approach.