Many devices these days are RF active and can permit criminals to track your movements or steal your identity. A cheap way to counteract this is with a static bag, commonly used for shielding sensitive electronic devices from accidental damage due to electrostatic discharge (ESD). You only need to drop your cellphone into one of these $10 bags and try to dial someone or receive a phone call to see that it blocks essentially all RF signals. The kind that zip closed like a ziploc bag are the best (sometimes called “faraday bags”). If you need to carry your phone with you but want to be absolutely sure your location and what you’re saying remain private, just remove the phone’s battery and drop the phone into one of these bags. It will shield your RFID-equipped passport, as well, which is nice since the government forces you to carry their insecure passports with you any time you want to travel across a border.
Clayton -