If there were a serious problem, this could be a great idea - but the fact remains that the kidnapping panic is based on fiction. In the 1980s a quasi-governmental group called the National Center for Missing and Exploited Children spread the word that 1,500,000 children went missing in the USA each year, and implied that these were children kidnapped by strangers. In fact, out of a current population of over 300,000,000 only about 150 children are kidnapped by strangers each year. As for the 1.5 million, almost all are teenage runaways, often counted multiple times (for each time they run away), and most kidnappings are by parents in custody disputes. Of course, any harm that comes to a child is tragic, but this moral panic causes many problems: more children will die early deaths due to lack of activity when they don't play outside than would ever have been murdered by strangers, and trust has broken down in society. It will be hard to recover from these blows that the NCMEC and similar criminal groups have given to English-speaking societies. These monitoring bracelets are another example of creating mistrust in society, which works to tear society apart. That said, such bracelets might be appropriate for toddlers, and maybe even children as old as 4 or 5, but for older children why has no one developed a similar device that is only activated by a panic button?