[jmnicolas]

Interesting experiment however his experience with tinfoil and metal boxes doesn't match mine.

I placed my phone wrapped in a towel inside a metal box: as soon as I close the lid I can't ping the phone on local WiFi and can't reach it with call (it goes direct to voicemail as if the phone was switched off). The GPS doesn't record any position while in the box. I didn't test the Bluetooth though.

Same thing for my car keys inside a paper towel and aluminum foil: impossible to open the car even at touching distance.

I wonder if he wrapped the device before putting it in the box or aluminum.

[mnw21cam]

I would note that GPS is much more fragile than WiFi/Bluetooth/GSM. The GPS signals are already incredibly weak at the receiver.