The rfid chip or tracking device is not something i would ever consider. There seems to be a more sinister reason behind this tracking device. However, we all could agree that it would make us feel more in control regarding our children whereabouts.
But lets say the predators know about it ? which if it becomes the next big thing they would all end up knowing anyway. What would stop the predator from cutting off their arms, or wherever this device is placed on your childs body!
For me, it would add an extra worry if ever (and God Forbid) my child were to be lost or taken. Media sells the idea by making everyone feel the need to worry that it can happen, because they play on our love and feelings of safety, No - i think there is something wrong with tracking devices. I don't even agree having them on new cars.
Are they good if our children get lost? maybe! but i still would not consider them...