Yeah, I'm working on a post about in-system travel too, since my feelings on it are generally the same as with bookend headmates (yes, you can do it safely/healthily, but it's Hard Mode), and a lot of the problems are the same, but there are a few special addendums.

BUT I suspect that plurals grabbed the "doubles" term from the fictionkin community because doubles was often a matter of contention back when "fictionkin" was still called "otakukin" (and honestly still can be in some fictionkin circles).

Interesting! Yeah, I've definitely seen the sentiment in fictionkin circles.