I gave up my use of cell phones about 2 years ago. Having police show up where I am politically active, ready for me, has been reduced. Emailing and talking on a cell phone about your plans is dangerous if you are part of the group that has, or is trying to connect the dots. Posting times, strategies, and meet up locations only makes it easier for the goon squads.
Having a GPS device on you, even off, might be an open mike or can lead police or their informants right to you. I was security on a film. We used police like radios with ear pieces. Getting equipment, a cup of coffee, others to help is instantaneously. When I'd go to the Hartford Capitol in Connecticut to speak at a public hearing, I'd face Connecticut State Troopers who would follow me around, give me menacing looks, and would follow me out to my vehicle, flashing their light bars just to scare me. I was also detained, to delay me from being able to attend public hearings.
The police and their informants get together and assemble target lists. They look for key people and then they spring traps or concoct to be able to arrest targets. Using like radios, and planning for meetings and strategy must be done offline, not posted on the internet, and not talked about over cell phones. If the Connecticut State Police were so infuriated with my proposing Civilian Oversight of Police to elected officials and for what I wrote in newspapers to enforce a "No Dating Policy" on me, mocking me on what I said on the telephone and in emails, don't expect any privacy of communication if you protest.
-stevengerickson AT yahoo Dot Com