>I would not trust that any modern smartphone is fully off without yanking the battery. That is not enough. Use a faraday cage. Modern phones have two batteri

>I would not trust that any modern smartphone is fully off without yanking the battery. That is not enough. Use a faraday cage. Modern phones have two batteries [0]. [0] http://electronics.howstuffworks.com/cell-phone6.htm http://electronics.howstuffworks.com/cell-phone6.htm