Not sure what the penalties for disclosing an NSL are, but companies sometimes use warrant canaries[1] for this purpose.<p>Notably the one used by Apple disappeared some time last year.<p>[1]: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Warrant_canary" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Warrant_canary</a>