A related / networked set of nodes is what I thinking of, similar to how climbing has a top, bottom, and bolt node but not connected visually with a way.
An ordered list of related nodes works for me.
I’d be fine saying the only acceptable use of something with true trail_visibiilty=no
is a ground truth hack to allow for routing of formal trails across small gaps. That sort of begs the question of whether trail_visibiilty=bad
should exist, although it’s probably not reasonable to expect every gap in trail to be broken into a segment and labeled. I do find small segments on trail in the backcountry more useful and appropriate than paths with varying strength and visibility.
I illustrated an example here of a short patch of trail_visibiilty=good
where IMO it’s not appropriate to create massively longer path to allow for routing. I also agree that these shouldn’t show up in standard routing so that kind of makes the point moot to me.