After a discussion with a lawyer friend (not australia, canada, so tangentially related), the "presumption of innocence" that would not obligate this person to have or produce a key for whatever gibberish someone sends to their devices, is what's known in legal circles as a "principle of fundamental justice," and it is not a right that is either absolute or inaliable the way that american rights are set up. One doesn…
Indeed and I wouldn't recommend any debate anymore. That ship has sailed 2 decades ago at least. While it shouldn't be that way the only option is technology. Technology made encryption a reality for many people and many governments didn't like that at all. I have no faith in the judiciary to set sensible rules for executive overreach so letting technology make safe communication a reality is necessary.
So we should always make sure to supply technology that allows for encryption and that the knowledge and development stays open enough so that it can be replicated.
In the end this will costs those governments massively in the long run.