content: Airgap is not gg if you want to defend against surveillance. You can gather data by the electromagnetic output electronics produce when they are working. The catchterm for this is tempest. One of the more famous examples was a guy running along wallstreet back when the big monitors were modern and showing people how he could reproduce the screen of the people in the building. This is also why movies showcase sometimes the hacker sitting in a faraday cage. It's not that easy though - if it's too thin it does jackshit. Supposedly the real secure ones got massive walls to be really secure and naturally any energy comes internally as the electric wiring could be read if it goes outside.