As this was said on national radio yesterday, I feel comfortable sharing it here. A caller to Glenn Beck said another issue is that when it is turned on, the GPS can pinpoint its position very closely so it is not only the communication that is insecure.
Even without GPS, the way a cell phone gets incoming calls is the cell tower "pings" it, and it responds "yes, I'm in range of you and able to take incoming calls".
The way we got Pablo Escobar in Columbia was with a piece of equipment which pinged his cell phone and triangulated on his position based on its response transmission.
There is a reason why Presidents didn't carry cell phones.
I heard that too. I wonder if they can turn that off or shield it? Otherwise, that is majorly dangerous.