The system of electronically-monitored ankle bracelets for offenders is flawed, say critics, following the case of a child sex offender who removed his bracelet and eluded police for nearly two days.
Daniel Livingstone lived in an Upper Hutt suburb close to schools and parks and is now back in police custody, to the relief of the community.
The GPS ankle bracelets cost around $500 a pop and it's now known it was these that were meant to keep the streets safe from the rapist and killer of Blessie Gotingco, Tony Robertson, and Livingstone.
Right now around 1800 offenders in the community are monitored using GPS technology.
Garth McVicar of the Sensible Sentencing Trust says it's not that difficult to cut the bracelets off with "a good sharp little pair of side cutters or a hacksaw".
ONE News knows of at least five cases in the past four months of offenders cutting off their ankle bracelets and fleeing.
In front of whose screen do these bells go off?- Professor Bill Hodge of Auckland University law faculty
"We're going to get more offending simply because of the category of offender they're granting it to now," Mr McVicar says.
So it's the monitoring system and response that's now sharply in focus.
"We should know more about how that works. And when does the bell go off and in front of whose screen do these bells go off and how rapidly can we react?" says Professor Bill Hodge of the Auckland University law faculty.
All tracking takes place at a monitoring centre in Wellington.
The Department of Corrections says if an offender tampers with the GPS device an alert is triggered and the centre sends a field officer to the offender's address.
In some cases police could be called and may arrest the person.
But in Livingstone's case, it took seven hours before they could determine he had fled, which worries Labour's Corrections spokesperson Kelvin Davis.
"The technology's there but if it's not being monitored or if there's no urgency in the monitoring then it might as well be not done at all," he says.
Mr Davis says Corrections needs to prioritise the highest risk offenders on GPS and response times to alerts for them need to be minutes, not hours.