What's the process for proposing a symbol in the Unicode table?

[Christoph Päper]

Asmus Freytag via Unicode <unicode at corp.unicode.org>:
> 
> We usually don't encode characters intended for use in handwriting, except if they are needed to digitally archive manuscripts. Not sure grade school papers pass that bar.

Every piece of writing might be digitally archived nowadays, even more so in the future. Therefore, every _established_ literal atomic sign should be encodable, so it can be unambiguously read by machines. I strongly believe this includes paralinguistic signs, whereas nonlinguistic signs (e.g. much of ISO 7000) would require an extension of the scope of Unicode (although several graphic symbols from that and other standards already have a codepoint assigned to them). 

This one is clearly well established, i.e. has at least one canonical form and meaning, even if its use is geographically limited. It cannot be represented by a combination of other, already encoded characters.