If you look through the old mailing list postings, the oft-left-implicit problem with Klingon (as well as Tengwar, Everson’s [EDIT: misspelling] pet project) is that it may get people into legal trouble (even though in a reasonable world it shouldn’t be able to). So in the unofficial CSUR / UCSUR they remain.

A weird solitary character from the 1400s isn’t subject to that, and even if it’s a mistake it’s probably not worth breaking compatibility at this point (I think the last such break with code points genuinely changing meanings was to repair a mistaken CJK unification some time in the 00s, and the Consortium may even have tied its own hands in that regard with the ever-more-strict stability policies).

Similarly, for example, old ISO keyboard symbols (the ⌫ for erase backwards, but also a ton of virtually unused ones) were thrown in indiscriminately at the beginning of the project when attempting to cover every existing encoding, but when the ISO decided to extend the repertoire they were told to kindly provide examples of running-text (not iconic) usage in a non-member-body-controlled publication. (Crickets. The ISO keyboard input model itself only vaguely corresponds to how input methods for QWERTY-adjacent keyboards work in existing systems—as an attempt at rationalization, it seems to mostly be a failed one.)

[EDIT: Removed a section about the now-fixed typo]

> I think the last such break with code points genuinely changing meanings was to repair a mistaken CJK unification some time in the 00s, and the Consortium may even have tied its own hands in that regard with the ever-more-strict stability policies[.]

Not exactly, the last break happened between Unicode 1.1 and 2.0 and the new CJK Unified Ideographs Extension A block still contains unified characters. The main reason for break was that both Hangul and CJK(V) ideographs required tons of additional code points and it became clear that 16-bit code space is dangerously insufficient; by 1.1 there was only a single big block of unassigned code points from U+A000 to U+E7FF (18,432 total), and there were 4,516 and 6,582 new Hangul and CJK(V) ideographs in 2.0 (11,098 total).

Unless it's legitimately someone's native tongue, conlangs shouldn't be in unicode. If there are kids out there that are native Klingon speakers, then you can make the argument it should be included.

I think it makes way more sense to put a conlang in Unicode than it does a peculiar stylistic flourish only ever applied once to a single letter in a single document. If that belongs in Unicode, why not every bit of marginalia ever doodled and every uniquely adorned drop cap / initial letter?

There is a smattering of missionary-made alphabets that have way less usage than some conlangs. Why are they legitimate but conlangs aren't?

so all you need is one crazy parent? shouldn't be too hard to find

https://www.dailymail.co.uk/news/article-1229808/Linguist-re... (2009):

“A linguist has revealed he talked only in Klingon to his son for the first three years of his life to find out if he could learn to speak the 'language'.

[…]

Now 13, Speers' son does not speak Klingon at all.”