It's going to be a very difficult legal debate at some point in the future. And I bet there are a lot of constitutional lawyers salivating over it :-)
If the government can compel you to hand over some information, well that's government. They can also injunct you not to tell people.
But, can they compel you to lie, publically ? Can they compel you to not publish such canaries - just in case they want to compel you later on?
And frankly, does it matter - is such a canary really just a form of social performance? If I don't want the US government to know something about me, I should stay the hell away from modern life, internet and so forth.
If the government can compel you to hand over some information, well that's government. They can also injunct you not to tell people.
But, can they compel you to lie, publically ? Can they compel you to not publish such canaries - just in case they want to compel you later on?
And frankly, does it matter - is such a canary really just a form of social performance? If I don't want the US government to know something about me, I should stay the hell away from modern life, internet and so forth.