> “I microchip my dog, why couldn’t I microchip my son?”
As pointed out, a dog is property, a son is not. Rights to property are almost absolute; rights to other persons have been pretty limited for a while now.
I got my cat through my local animal shelter. They require a microchip. That way, when they find the cat dead in the street, they can scan it, find the adoption records, and notify me of my loss. I don’t think that is as helpful for children.
My neighbor cat wears a fat collar — and it has a cellular uplink that allows my neighbor to track where the cat is during the day. It is interesting, but again of limited utility, since in general the cat wouldn’t be at an easy place to recover them from (I think the granularity is around 50m) but again if it stopped moving for an extended period of time, it might be helpful to recover the body.
But really, I think for a child the point wouldn’t be to prevent kidnapping but to track movements; I think parents protection rights trump a child’s privacy rights. On my cell phone, I have an app, “GPSlogger” that will periodically wake up and send a GPS trackpoint to file or remote server. I used local files, but it would be trivial to use it to know where the phone was. So give the phone to the child; if very young, sew it into a pocket, and if older tell them to keep it with them. There might be compliance issues (hey, would you hold my phone for me? I want to go over to the wrong side of the tracks…) but that is a helpful thing between parent and child.
So implanting just means you can’t trust the phone to stay with the child — that the child is so willful he would reject your control (in which case you have a far bigger problem) or that he would be forcibly separated from the phone. As noted, child abductions are very rare, and in most cases the child is killed within three hours of the abduction. So again, we are back to making it easier to notify me of my loss.