A little more than a year ago, California began testing the GPS monitoring devices that track the movements of thousands of sex offenders.
The results were alarming.
Corrections officials found that the devices used in half the state were so inaccurate and unreliable that the public was “in imminent danger.”
Batteries died early, cases cracked, reported locations were off by as much as three miles. Officials also found that tampering alerts failed and offenders were able to disappear by covering the devices with foil, deploying illegal GPS jammers or ducking into cars or buildings.