Cell Phones Track Your Location

I din't know that until I heard this news on the arrest of a London bombing suspect:

The 27-year-old Briton who was arrested in Rome on Friday and accused of planting a bomb on a British subway had entered Britain using fake documents and an alias, the authorities say. He managed to escape the country on the Eurostar, although grainy photos of him plastered the walls of the train station.
Yet the police swiftly tracked his escape, for the most mundane of reasons — he did not turn off his cell phone.
..."If your phone is on, they know exactly where you are," said Paul Sagawa, an analyst with Sanford Bernstein, an investment research company in New York City.

This feature was announced in early 2001. The FCC now requires it for 911 services.
Today, this feature is being marketed to parents who want to track their children.
One Security Tech Blogger is not impressed.

This is worrisome from a number of angles: government surveillance, corporate surveillance for marketing purposes, criminal surveillance.
...We're building an infrastructure of surveillance as a side effect of the convenience of carrying our cell phones everywhere.