Personally, I don't have a problem with this, since I neither violate the law, nor care if people know where I am. And frankly, it would solve just about every missing person case period, (and I really do fear for my niece when she goes to the "mall" - she walks there and it's 5 miles from her house) not to mention make it insanely easy to figure out who is committing a crime in progress.
That being said, I don't really want it. Because I know some people will abuse it.