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[...] the UTC does not wish to entertain further proposals for encoding of symbol characters for flags, whether national, state, regional, international, or otherwise. References to UTC Minutes: [134-C2], January 28, 2013.
This is also why U+1F3C1 CHEQUERED FLAG doesn't set a precedent for encoding additional flags as single characters: it was also introduced in Unicode 6.0, more than two years earlier.
-- Doug Ewell | http://ewellic.org | Thornton, CO 🇺🇸