Danes tag kids with Bluetooth
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Parents can buy a armlet for their child for DKK 20 (about $3). Should a child wander off, they merely have to send a SMS requesting information on the particular tag. Shortly thereafter they receive a message back specifying the location of the child's nearest Bluetooth receiver. The access points can pinpoint the location down to 20 metres.
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"Good, get get an armlet for little Suzie and let her run around without me. All I have to do is page her when I'm ready." to "What do you mean she's not found?"
May make some parents less vigilant when out with their children.