It not only happens on TV dramas.  Police can track cell phones in some instances have done so without a warrant.  New evidence from the American Civil Liberties Union shows that phone location tracking has also become a common tool of law-enforcement investigations, but often without a warrant.

The ACLU recently obtained records from over 200 police departments and other law enforcement agencies around the U.S. They found that "virtually all" of these agencies track the location of cell phones with data supplied by wireless carriers.

Catherine Smit-Torrez is a former police chief turned private investigator/security expert with 22 years in law enforcement.  Today on “Mornings With Ken & Bernie” she said if you don’t want to be tracked “put your cell phone in airplane mode or turn it off”.  Smit-Torrez says location tracking is inherent in how cell networks function; otherwise nobody's cell phone would ring.

Listen to the interview with Smit-Torrez: Catherine Smit-Torres Interview 040612