It would be great to show unlinked relationships. For example:
alias: []
tags: [rpgm/element/character/npc/1]
synopsis: "A resourceful teenager who runs errands for Ibis."
goals: "To become a FastDev. And to punch that asshole Becky in the face."
pronoun: she/her
dates:
dob:
death:
relationships:
characters:
Ibis: "A kind of older sister to Telma. Not that Telma will ever admit it."
Parents: "Mother is AWOL."
factions:
locations:
completed: false
In the case above, Ibis is a character with their own page. But "parents" definitely are not, being a kind of "relationship" note that I find relevant in this character's presentation. Ibis appears in the display block, with a link to her page, but "Parents" won't appear at all unless I create a page for that, which is unnecessary.
I believe that allowing un-linked relationships to appear is useful both to add extra bits of info in a handy, intuitive location, and it's a cue for relationships you intend to create notes for later.