[westicle]

Fair enough, I agree that these laws are a mess and you'll never get the final answer unless a disputed application of the Act is determined by the High Court.

But these laws have been active and in common use for over 10 years without a single public challenge. I also know that the ACC's interpretation of their own powers has been used to prevent suspects disclosing certain matters even to their own lawyers.

The fact that no high-profile judicial decisions have placed limits on what the ACC does indicates to me that the law is fairly settled in this area.

I just wanted to point out that the original statement "Australia does not have any equivalent to the US National Security Letter, so we cannot be forced to do something without being allowed to disclose it." does not seem well-founded.