Can a provision in Direction 90 cover the field?

Para 8.4 of Direction 90 provided:

(1)     The Australian community expects non-citizens to obey Australian laws while in Australia. Where a non-citizen has engaged in serious conduct in breach of this expectation, or where there is an unacceptable risk that they may do so, the Australian community, as a norm, expects the Government to not allow such a non-citizen to enter or remain in Australia.

...

(4)     This consideration is about the expectations of the Australian community as a whole, and in this respect, decision-makers should proceed on the basis of the Government's views as articulated above, without independently assessing the community's expectations in the particular case.

Some of the questions to the Full Court of the Federal Court (FCAFC) were as follows:

Question 1: Did the members of the Full Court of the FCA in FYBR agreed that "the expectations of the Australian community, as expressed by the Government in the Direction, do not determine the outcome of the decision because all relevant factors have to be weighed up and considered"?

Question 2: Is it correct that Direction 90 sets out guiding and mandatory considerations, (i.e. that not all of what it says is mandatory)?

Question 3: Is the word “should” in para 8.4(4) indicative of a requirement that must be followed (i.e. that is mandatory)?

Question 4: Is one of the meanings of “should” to convey duty or obligation rather than merely guidance?

Question 5: Is it doubtful that the Tribunal can permissibly have independent regard to community expectations as assessed by it, given the Direction’s express provisions with regard to that subject which can be expected to cover the field?

The FCAFC answered those questions as follows: