I'll bet your thinking. People will never allow themselves to be "coded"!
"The Food and Drug Administration in the US has approved the use of RFID chips in humans.[73] Some business establishments have also started to chip customers, such as the Baja Beach nightclub in Barcelona."
All you have to do to start the ball rolling is make it "trendy"!
Removed from a credit card. "Whats in YOUR wallet?"

H&K, and Sig has used them to make guns for police departments that "only an officer can fire". So in reverse... A chip in your gun could be made to NOT fire within 30 feet of an officer, or other RF signal carrier. Hmmm.