1. the chances that a random old device you bought at a fleamarket with cash is pre-loaded with an attack package thats targeted to you is low. Lower than say ordering a phone in its &quot;originaly sealed&quot; package. Since Snowden we know that Hardware is intercepted and modified. I am sure the package looks sealed afterwards.<p>2.Installing a ROM without the normal Google apps is something that is beneficial for this application.<p>3. in all the android phones i have taken apart the various antennas are easy to identify and remove. they are part of the back shell and can be peeled off or are sitting on their own little module that can be left out of the phone.