I can attest that most US military electronics are in some sort of Faraday cage system, to ground out an EMP. EMP has been a concern of military design for a goodly long time now.
Whether civilian systems are, say a private server in a Chappaqua closet, present poster knoweth not... It's not like a copper mesh box grounded to a water pipe is high tech.
Be too bad if they weren't.
Yeah, used to work with a guy who was part of satellite work on a non-DOD “rad hard” bird.
And then there’s fiberop comms installed what, 30 years ago?