> Physics isn't really an issue. Locator beacons are a thing. But they're standalone GPS size (i.e. not watches) and have subscription fees in the $100+ per yea

> Physics isn't really an issue. Locator beacons are a thing. But they're standalone GPS size (i.e. not watches) and have subscription fees in the $100+ per year category. These caveats are caused by the physics. They're mostly batteries and antennas due to power constraints, and operating the receivers is expensive even with the tradeoffs they make.