This, via Near Near Future and Engadget, is scarily going to be the way of things to come I fear. GPS tracking technology is going straight into the fabric of school uniforms in Japan so that parents will know where they are at all times. They even have panic buttons on them which will alert the nearest security guard.
I worry about this kind of thing, even though I admire the technology. Kids need a degree of freedom and really they need to learn about risks rather than always be sheltered from them through technology that invades their right to privacy.