Is asking police to justify their orders illegal?

Question

From the BBC, WRT instructions by the police for people on the streets to move on:

the legal niceties don't always matter: "The police will often just insist on people 'moving on' because they have been asked by the local authority to clear the street, but without quoting any specific piece of legislation. Naturally (and wisely), people usually don't ask under what legal provision the police officer is asking them to move." To do so could be interpreted as a breach of the peace or obstructing a police officer, the Shelter expert says.

From my position of having a home and not being particularly oppressed by the state this seems incredible to me, that a simple request for justification could result in criminality. This leads to two linked questions:

1. From a legal perspective is it possible to commit a crime such as breach of the peace or obstructing a police officer by requesting the legal justification for a order from a police officer such as "move on", given that the legality of such orders are highly questionable?
2. From a practical perspective have people been arrested and/or charged with a crime for requesting the legal justification for a order from a police officer such as "move on"?

Answer 1

Is asking police to justify their orders illegal?

NO but the manner in which the "asking" is done may be.

Answer 2

Asking is not illegal

In fact, the police must tell you the reason for the direction to be valid.

new-south-wales

s197 of the Law Enforcement (Powers and Responsibilities) Act give police the power to order people to move on if they are obstructing pedestrians or traffic, they are intimidating or harassing others, they are placing others in fear, they are supplying or receiving prohibited drugs.

s198 gives them the power to move drunks along if they are a risk to people or property or are disorderly.

s199 extends both the above powers to groups of people.

s200 sets out the fine for non-compliance: 2 penalty units (currently $110).

Requirements for validity

All of these directions must be given in compliance with the Code of Practice which requires:

• providing evidence they are a police officer (unless they are in uniform), their name, place of duty and the reason for the exercise of the power. This must be done as soon as possible and, when directing an individual, before the direction is given.
• informing the person(s) that they are required by law to comply with the direction (unless they have already complied),
• when exercising the drunk power, informing the person that they cannot return to any public place for 6 hours.

However, s204A provides that even if the requirements above are not met, the order is still valid if given to a group unless the officer was asked to provide the information and didn't.