Cell towers are constantly tracking the location of mobile phones. And that data, federal courts have ruled, is not constitutionally protected. Steve Greer/iStockphoto.com hide caption

toggle caption Steve Greer/iStockphoto.com

A college student spent the night in jail and was charged with felony counts after agents approached her car, suspecting she bought beer at this Harris Teeter grocery store in Charlottesville, Va. Google hide caption

toggle caption Google

NPR thanks our sponsors

Become an NPR sponsor