Taking Battery out of Cellphone (not necessary) So long as you are not concerned about the CIA, FBI, your phone company's security people, or the Scientologist's ability to infiltrate those organizations in a significant manor, or if Scientologists have obtained physical access to your cellphone with sufficient time to hack into & install trojan software, you don't need to remove your cellphone battery. If you do think the above agencies have been significantly infiltrated then you are pretty much fucked anyway since (depending on your model of phone) they can install software to do whatever the frak they want. IF you have bluetooth (that thing that connects to your wirelesss ear piece) enabled on your cellphone, the worst they can do is to send messages to your cell phone within a 50 foot radius. Other than that, they either have to get you to pair your phone with one of their own devices (you would know if you did it) in order to get any information off of your phone. Or they would to be able to install software on your cellphone via your phone company or with physical access to your phone. ETA: Turning off your cell phone should be more than enough security at these events (so long as you are wary of pickpockets).