You are certainly not alone in worrying about your kids ... I raised three daughters in an urban environment that got pretty scary at times. Hell's bells, my "baby" turned 26 this year and I STILL worry about them. Why, they could bring home a Grogan or something.
Still, there is something downright Orwellian about implanting a tracking device in them that I just can't get around. I know that bad shit happens today - but if you watch and read the news carefully and thoroughly, you'll see that the biggest dangers to most children face come from where they've always come from - right there at home. That fact doesn't sell much soap, ketchup, or sanitary pads - but it's true.