Comment by Gibbon1
A while ago saw someone who was working in the tracking space said the following.
For stolen items you don't want to track them. You want to be able to ask them where they are. The advantage is you can make a locator that doesn't reveal itself by transmitting. And it doesn't waste power receiving gps signals. You could literally have a device that runs for years on a AA battery.
The reason you don't see these on the market is because the people that fund products want to sell location data.
That's how classic Lojack worked. Lojack is a car theft detection device. It's not GPS based. It's hidden somewhere on the vehicle and connected to power. It listens to FM broadcast radio stations until it finds one with the Lojack subcarrier, something Lojack licensed from radio stations in most cities. It decodes the subcarrier, listening for serial numbers of Lojack units that have been stolen. Then it starts transmitting. It doesn't transmit location, just its serial number. Police cars equipped with Lojack receivers get an indication of direction and distance. Lojack had an effort to equip police cars with the equipment. At peak, LoJack had coverage in parts of 29 states.
It was very effective. 98% recovery rate.