Given that police are probably at greater risk of 'weapon retention' failures than CCW holders in general, it would seem that they should get the greatest benefit from this sort of technology. Any many of the technical problems people have discussed could be worked out (e.g. using a long-enough encryption string that wrong-code lockouts would be unnecessary, and designing the implanted chip so that it wouldn't give any response whatsoever except to a transmission that was specially coded for the chip).
If the cops, who would get the greatest benefit from the technology, have to be exempted from it, that would suggest the technology really isn't very good.
They'll have to plant the chip in my dead body.