[MereInterest]

A related concept is the warrant canary, which is a positive statement that the government has not accessed user information. It is current untested in court whether the PATRIOT Act can compel speech, or merely silence it, and so the idea is that if you stop making the positive statement that no government intrusion has occurred, then it implies that there has been intrusion. (The constitutionality of Section 215 of the PATRIOT Act has, to my knowledge, never been tested in court, and I firmly believe that it violates the First Amendment's protection of free speech.)

That said, they are generally ignored when they disappear. Apple and Reddit both removed their warrant canaries in 2016, to very little fanfare, despite the implications of them doing so.

https://en.wikipedia.org/wiki/Warrant_canary