I recall reading that during the Occupy protests, the phone companies worked with police to thwart the protestors. They (police and phone companies) created zones where messaging/testing abilities were disabled so protestors couldn't communicate/organize. I believe the term for this kind of activity is referred to as "geofencing".
Printed copy · Anthology Volume 4, page 1211Printed copy from The Tender For Law Anthology, Volume 4, page 1211 (printed 13 June 2014). Added by this site; not part of the Facebook export.