What made you decide to use it? How did the children respond to it? I was watching Nanny 911 and the 6 year old and the 2 year old had a habit of running outside without permission. The nanny's solution was to get a Giggle Bug tracking device. (Actual product. I looked it up: Add to Cart) I used to say that I thought it was a bit much if teenagers had that in their phones or in their car, but I think nowadays, especially with young children, something like this would be very useful.