It has not made the NEC as far as I know unless you want to get fast and loose with "metal that may become energized" but the Florida building code addresses it directly.
SECTION E3302 BONDING METAL FRAMING MEMBERS
E3302.1 Metal framing members. Metal framing members shall be bonded to the equipment grounding conductor for the circuit that may energize the framing and be sized in accordance with Table 250.122 of the National Electric Code. For the purpose of this section, a grounded metal outlet box attached to the framing shall be permitted.
This is one of the few additions to the NEC they have.
