Good to know I'm the go-to guy for so many of you when you find the latest childtracking technology. A whole mallful of you sent in the link to Bluespan's IonKids wireless bracelet/base station proximity monitoring system over the last couple of days.
After hearing from so many parents of autistic or Down syndrome kids about how insensitive I was for mocking the Wherify GPS tracker, I'll say straight out: If you like this kind of thing, then this is the kind of thing you'll like.
In their pitch, their functionality, design, and target market, IonKids seems to navigate around most of my objections against gen-pop kidtracking, the debilitating Big Brotherliness and the likely guard-dropping that comes from over-reliance on technology. They readily address the needs of parents with special needs kids, and their use scenarios don't involve ignoring the children while you drink sweet tea or avoiding black people.
IonKids uses the same radio frequency as cordless phones and garage door openers, and you can ratchet the signal radius up to 300' or down to 20'. You can monitor up to four kids at once, and you flip that bad boy open, you can locate one by direction and distance. Very Goldfinger.