This is the correct advice. Postal abbreviations should be used for postage only. If you're a newspaper writer who for whatever reason is constrained for space,

This is the correct advice. Postal abbreviations should be used for postage only. If you're a newspaper writer who for whatever reason is constrained for space, feel free to use Associated Press abbreviations like "Calif." if and only if it's preceded by a city. In all other cases, spell it out. Nobody should have to think more than a nanosecond what state you mean when you write MS (Mississippi? Missouri? Massachusetts?) or AK (Alaska? Arkansas?).