This is why you sign the canary regularly, and then it just expires if you do nothing.
Although... I also don't see much use in them either, it seems everyone ends up complying with something eventually and so all canaries end up getting removed.
IANAL, but I'd think that hurting your possible future defense is what you just said, and what people always say: that the premeditated intent is to violate a potential future gag, and that removing the canary (or not updating a cryptographic signature, or resetting to 0 the "__ days since last served a subpoena" notice) is a mechanism for that violation.
IMHO, that's kinda a weaselly trick, no matter how good the cause, and it might not stand up, not legally, nor in extra-legal practice.
Not a lawyer, but I think the government has more ability to prevent you from doing something than forcing you to act.
They can tell you to not remove the canary, and not tell anyone your logs are being monitored, but it is trickier for them to say you must re-sign this certificate.
That sounds like much more of a nuanced law question than a "are these the same".
While they might be able to stop you telling the world, they might not be able to force you to perform actions that cause you to lie to the public
Although... I also don't see much use in them either, it seems everyone ends up complying with something eventually and so all canaries end up getting removed.