[MichaelBurge]

Suppose you get an email from the boss saying, "singlow, remove the warrant canary script from cron. I just got out of a meeting with the Board, and they all agreed we need to inform the public that we've received this national security letter."

If you truly believe your argument, you wouldn't prosecute the boss even in the presence of this email. We all know anyone planning on using a warrant canary is intending to inform the public, so whether or not there's an email admitting it should be irrelevant if the action is legal. If you believe that the boss is not guilty, then you're consistent in your position.

Now, as a practical matter, you'd use an in-person meeting or telephone call or something. Or you'd at least use different wording. But the act itself would in principle still be illegal, even though there is no evidence to prosecute. And in that sense, a warrant canary could be a useful tool to allow one to get away with a crime that they consider unjust.