You might have seen the news that the AFP accidentally forgot (whoopsy!) to get a warrant before accessing a journalist's metadata to try to trace a source.
A bunch of law enforcement agencies can access stored metadata without a warrant. When the metadata retention rules were introduced there was a lot of concern about access to journalists' metadata to identify sources and the chilling effect on press freedom and free speech.
To address the problem, the pollies quickly concocted a regime requiring a warrant to access a journalist's metadata. The rules are pretty flimsy in terms of actual protection for journalists and their sources. Journalists have no knowledge of a warrant to access their data being issued, and no opportunity to oppose it. Their interests are left in the hands of a public interest advocate, appointed by the PM, who acts in the broad public interest and not the journalist's or source's interests specifically.
The failure to get the warrant means that nobody considered the public interest in protection of the source that the AFP were trying to track. There could be some very good reasons to protect a police whistleblower, like the broad public interest in disclosure of anything smelling like corruption, not to mention personal safety. The AFP saying that they will destroy the information that they accessed is no help if they've already used it to identify the source in question.
The fact of the AFP disclosing the breach on this occasion is also a bit odd. It's a crime to disclose pretty much any information about journalist information warrant, including the existence or nonexistence of a warrant. So, if it's a crime to disclose information about the nonexistence of a warrant, AFP Commissioner Colvin should be looking at some serious hot water.
Perhaps the AFP think of the journalist information warrant regime is a bit like the pirate code. More what you'd call "guidelines" than actual rules.