Unfortunately, this product is about 12 years too late for me to take advantage of it. We looked high and low for such a product back in 1997 after my son continually wandered away from home. At that time, there were just a few products becoming available for Alzheimer's patients, but nothing in the children's market. We even contacted a few research organizations that were producing collars for tracking wildlife. Their products would have worked but they couldn't market them for use with humans.
If you have an autistic son or daughter who wanders, you will RUN to get this for the peace of mind it can provide. My son was able to outwit, evade, and overcome all the household locking devices we could generate (aside from a keyed deadbolt that would have been problematic in case of a fire.)
Seriously, this device will give some parents peace of mind.
NOTE: My son was always found, without harm, but only after a great deal of effort at times, including the bulk of the police force in Fort Collins at one point in time. Today he's a fairly well-adjusted sophomore in high school.