I like cell phones. But the downside is they are totally taceable. a member of the law enforcement community can track the movements of every phone and record every conversation. Not just that but they can tell where you where at the time of the call and to top it all its a microphone in your pocket earwigging on everything.
The only safe solution is to not just turn it off but pull the battery out like a bad tooth. especially before you are about to discuss confidential matters.
use new sim cards regularly and even consider vhf 2 way communication.
there are lots of dudes languishing in chains because of cellphone technology.

Be careful out there.