Interesting article from Bloomberg: What’s the Maker of Post-it Notes Doing in the Ankle Monitor Business? Struggling
Net/net - their ankle monitors suffer from a variety of problems that falsely indicate that a wearer of the device has disabled / broke / escaped, etc:
There were problems from the beginning, according to corrections officials, offenders, and attorneys. For example, the battery on the bracelets was prone to dying suddenly and without warning. The internal antenna didn’t always perform well underneath certain clothing or in certain buildings. The devices sometimes relayed inaccurate navigational coordinates, leaving offenders in technical violation of the conditions of their release. Some offenders found themselves having to walk outside in the middle of the night or stand in the middle of a street to establish a satellite connection and prove to authorities that they were where they were supposed to be.
Yet another example of why security systems demand high accuracy and the problems that happen when they do not.