I know the rule. What I'd like to know is what the rule is protecting me or someone else from. It's certainly not an electrical thing, given that the difference between blue-marked-white and white-striped-red is insulation color.
What I can see is if there is 3-phase wiring in the building, someone could try tapping the circuit in the middle where they won't see the remarking of the blue, and hook up something like a 3-phase motor. They might be inclined to do that with a 6 AWG or smaller conductor thinking it's an ordinary circuit, whereas seeing something larger they are less inclined to mess with it.
What hazard would exist if the rule were changed to allow remarking blue as white in the narrow circumstances of only 1 or 2 family homes that have only single phase power?
