From: grarpamp <grarpamp@gmail.com>
(or as Snowden demonstrated, put in a fridge to avoid scrutiny and
audio capture the best idea. non-serial tower associations are an anomaly alerted and acted upon.)
Faraday cages concept really depend on the freqs they are designed
to inhibit, pressure, sound, radio, optic, etc. Given wide enough freqs, one cage does not service all. A fridge has plastec and magnetic gaskets, over maybe 2cm variant gap, so not a complete EM seal (at whichever specifical freqs). And grounding issue. But good at human sound deading. Microwave door shield is closer to cell phone freq shield. If you cannot simply remove the battery preferably, that is. As always, test first. And is easy to find phones to test all phone bands with. TEMPEST.
Why not wrap the phone in a couple of layers of aluminum foil? (Although, it won't shield against audio if that's being recorded even while an RF contact does not exist...) Jim Bell