George:
FWIW, Caddy made/makes a clip that is intended to identify ceiling wire used for support of cabling.
I don't have a Caddy book handy, but:
Painted bright yellow, 3 to 4" long, one end has a hole for the wire to go thru, other end clips onto the 'T' bar. Support wire cannot flap in the breeze, so this Caddy secures the lower end. With the bright yellow paint, as long as the AHJ isn't color-blind, it's a no-brainer.
