When reading debates about reserving the digital space (not necessarily the typographic form) of certain characters, I always liken it to a typographer creating fonts for an advertisement. If the letter "g" is not needed for the ad, and the font is developed for the ad, why should the "g" glyph exist? If they release the font file (or it is extracted somehow) if "g" was never created, the space for it will exist, there will simply be no glyph for it.