Re: Reversed polarity receptacles
Of course proper "polarity" of the wiring is important & NEC requires it.
NEC does not tell you why it is important, because that is not the purpose of the NEC.
Those of you old enough or "used" enough, may recall the days of 2-slot receptacles, no polarity standards, 2-wire cords on metal-frame drill motors & radios, the virtual non-existence of equipment grounding (bonding), etc.,etc.
It was not too uncommon to hear of someone being electrocuted. It was a bad deal. As an electrical professional, sometimes I feel maybe a little embarrased that it took "us" so many years to right some of these wrongs.