Check out Anita Ramasastry's latest Cyberlaw column at Findlaw. Good reading:
FindLaw's Modern Practice - Every Move You Make, Part Three: Why Law Enforcement Should Have to Get a Warrant Before Tracking Us Via our Cell Phones:
We have a reasonable expectation of privacy with respect to our movements, as we go about our daily business. Though sometimes we may be seen by passersby and by security cameras, at other times we will not be; and sometimes, we will be in the privacy of our own homes or offices when we carry our cell phones. Our expectation of privacy should be honored, as the Texas and New York courts held.
But other courts in other jurisdictions have held otherwise. For that reason, Congress should now step in and ensure, by statute, that the warrant requirement applies under these circumstances.
The balance of privacy and security is a delicate one - and the warrant requirement is an appropriate check on law enforcement's ability to track, via cell phone data, every move we make....
Thanks to Sabrina Pacifici's beSpacific for the link: beSpacific: Commentary on Privacy and Cell Phone Tracking.