An old iPhone5 (or a dedicated device) with that fingerprint ID thing is a GPS tracker that you could be required to check in with at regular intervals. They would know where you are, and that it is you, which would come in handy for verifying community service (heck, with the accelerometer they’d know how many calories you burned picking up roadside garbage) and if that’s too much of a problem go sit a community justice center instead.
No real need to implant it. The next generation is already tethered.
