This service could be useful, but being part of the "new" generation that sondjata is talking about, I still fear privacy concerns. Lets say, every day at 3, I have a job working at a sewage facility. I don't want my friends to know that, so I switch off my location. Now, if they are good friends, they will understand, but otherwise they will question why I always turn it off.

Other than that, Google does not give a sh*t about your location. The government can already track your phone (911 calls anyone?), and if you are really scared of the government, you would not carry a phone.

I think it is a great idea for the most part.