The idea with a canary is that some government request can stop you from disclosing that request ("hey everyone we got subpoena'd") but they can't stop you from

The idea with a canary is that some government request can stop you from disclosing that request ("hey everyone we got subpoena'd") but they can't stop you from NOT updating a page. Putting a newspaper headline on the page basically provides a timestamp so anyone checking can go "hey, their canary hasn't been updated in 6 months... maybe something happened". At least that's my understanding of it.