It's not a novel idea to make criminals wear GPS bracelets, but they could soon be relatively commonplace in the UK. The country's government plans to use them for around-the-clock monitoring of criminals across England and Wales by the summer, with a handful of regions already putting them to use. They'll be used to both track behavior when out of prison (say, to ensure offenders attend rehab) and enforce geographic limits like restraining orders.
The government estimated that roughly 4,000 people will receive GPS tags each year, but no more than 1,000 people will wear tags at any given time.
As with earlier uses, there are ethical advantages and drawbacks. This could avoid or reduce prison sentences for minor offenses, and more effectively monitor serious criminals when allowed to reenter society. The current electronic tags can indicate if a wearer is present at a given building, but it's not much use outside of those narrow conditions. However, it still amounts to 24/7 location tracking for people who, in some cases, committed only non-violent crimes. While convicts aren't about to earn much sympathy, there's little doubt that they're losing a lot of privacy.