Canary statement
noun
1… A small songbird in the finch family, serinus canaria domestica, originally native to islands in the North Atlantic.
2… A mechanism to test for unsafe conditions, originating from the use of canaries in coal mines to detect poisonous gases or cave-ins. If the canary died, it was time to get out of the mine. More recently, the term has been used by some online service providers to refer to an affirmative statement, updated regularly, that the provider has not been subjected to certain legal processes. If the statement is not updated in a timely fashion, users may infer that the canary statement may no longer be true.
▻https://canarywatch.org/faq.html
For example, an #ISP might issue a semi-annual transparency report, stating that it had not received any #national_security_letters in a particular six-month period. NSLs come with a gag, which purports to prevent the recipient from saying it has received one. (While a federal court has ruled that the #NSL gag is unconstitutional, that order is currently stayed pending the resolution of the government’s appeal). When the ISP issues a subsequent transparency report without that statement, the reader may infer from the silence that the ISP has now received an NSL.