When Edward Snowden met with lawyers in Hong Kong in 2013 to get legal advice after he told the world about the National Security Agency’s (NSA) spying program, he asked everyone at the meeting to put their phones in the refrigerator.
It was an odd request, but the idea was that the thickly insulated metal walls of the refrigerator (not the temperature inside), would act as a shield. Something like a Faraday cage, the refrigerator would prevent eavesdropping.

