Here's the tricky bit. Ought one track criminals after they have served their sentence?
Many feel that it must be distinguished by the criminal. There is little sense in tracking white collar criminals, for instance, but sex offenders—who already have lists of their name and location published publicly—are a hot target for tracking devices. The idea is that by actually enforcing existing restrictions on their movement, such as being within a given distance of a school, will work to prevent further offenses by repeat sex offenders. Another use is to enforce restraining orders, which might also prevent many deaths by the hands of violent stalkers or exes.
Still, at least in theory, these people have already served their sentence: after they have done so, why continue the punishment? GPS tracking devices are large and conspicuous, and what certainly interrupt the daily life of a criminal once free, preventing them from reintegrating into society and thus making them even more likely to resort to crime again. And then there are the privacy issues: once free, does a government body, even in the name of prevention, have the right to such a deep invasion of privacy as tracking location? Some have argued lifelong tracking as mandated by many states as unconstitutional. This is a tricky dilemma to resolve.
And, ought GPS tracking systems replace traditional incarceration? Maybe not in all cases—murder being a good example of this. Jail is as much punitive as keeping people genuinely dangerous to society off the streets. But for minor crimes, many people see it as just a more restrictive parole, a much more constructive way to rehabilitate someone.
Another nice little advantage of this system is that those who have committed soft crimes won't be exposed to hardened criminals, a notorious problem where people who just committed minor crimes are transformed by their jail time into something that society really has to fear.
Still, the danger of letting criminals out on the street before they've learned their lesson is a frightening one, and one that people aren't likely to abide by without some serious protections.
For some excellent pieces discussing this complex issue, check out both the links within this article, and the following:
More States Move To Use GPS Tracking of Sex Offenders – Fox News
GPS sex offender tracking. Detailed breakdown of terms, laws and costs.
Why GPS tracking is good news for inmates – Slate.com
Attack of the Perv Trackers – Wired.com