Earlier quoted context omitted.
In the case of NSLs, or UK orders from the security services, it may be illegal to tell anyone who isn't mentioned in the order. Including the company's general counsel. In the event that you are asked to do something illegal, it may be illegal or inadmissible to mention that you were ordered to do so by the government (Matrix-Churchill trial passim)
I wonder how they think this is supposed to work. - CEO gets a Letter. Does the CEO start learning Python/C++/PHP and Cisco configuration? Or does he tell a worker bee "Shhh! And read this Letter" ? - Worker bee starts making changes to production code and systems. Suddenly he starts needing automated code reviews, and reconfiguration alerts go out when he frobs the firewalls. These changes are indistinguishable from…
I don't know how Yahoo is organized but if teams works in silos, without any visibility on other teams, it is probably not that hard to introduced changes that are undetected.