How about: "Wiring that is not being used, but is in good enough condition to be used in the future, shall be tied to equipment ground inside the circuit breaker panel and inside junction boxes, etc. Wiring that is no longer suitable for service shall be removed where practical, or if not, tagged and tied to equipment ground."
Tieing unused wires to ground should minimize the "unused hot wire" problem. And would supplement the equipment ground.
