I can see one use for them as a way to try to monitor geographical restrictions. You could be very quickly alerted that a sex offender was now nearing a playground or that a gang leader had left his house to do who knows what. It could be helpful in perhaps alerting authorities quickly and maybe intervening before something serious happens, but it's not going to change their long-term behaviour. It's not going to make them pro-social citizens.
On February 9th, 2012. See this statement in context.