Do You Know Where Your Children Are?

A service in Britain called mapAmobile can pinpoint the location of a cell phone user within 50 yards. It's being pitched as a way for parents to keep track of their children, which may dull the appeal of the now-ubiquitous devices for teens. There's some built in privacy protection, of course: subjects have to confirm their participation via text message, but the general idea is still unsettling. A less scrupulous company (or, perish the thought, government) could just as easily decide to offer the service without those safeguards, couldn't they?