In 2021 the most powerful canary statement should be "Don't trust us. Seriously, treat us as an adversary. We still want you to be our customer of course, but here's how we really recommend you use our service, Tor, semi-anonymous payments, etc. In God we trust, for everyone else use math."
Would love to sign up for some Tor-first services. So far the best we've got are Tor services that mirror public ones.
I admit that the marketing is bad, I do not agree with it, and I do not tolerate it in terms of my own OPSEC. But, there's just no way they would just admit they provide hardly any value besides, in a VPN's example, being a tube to another place, and just another tube with ends that can be stopped.
What is far less clear is if you can trust the continuation of a canary statement to indicate the absence of the action it denies, since it is both legally disputed whether continuation of the statement could be mandated by government and because anyone who has an interest in the PR value of providing a canary statement also potentially has the same interest in continuing it as long as it is impractical to falsify.
Is compelled speech seriously in jeopardy? I saw the github issue for signal saying that some (EFF?) lawyers said that canaries are not that helpful, but that just implies that the government CAN compel speech. That would be bigger news than mentioned as an aside on a Github issue, I'd like to believe that would be news...
In fact, it turned 15 years old this past April[3].
[1] https://www.rsync.net/resources/notices/canary.txt
I was referring to Protonmail's canary specifically, in the event that wasn't clear.