David Eddy wrote:

    "So why haven't you stopped her?"

    "I'm a guest here."

    Akane frowned for a long moment before Ranma's meaning became
clear to her.  A guest could not act against his or her hosts...
and a guest was entitled to protection and honour from his - or
her - hosts.

This is AFTER volume 38?  Ranma didn't mind acting against Nabiki, sort of,
in volume 35,
in the "Just the two of us home alone story".  He chased her to get film
away from her and
then grappled with her.

    "Well *that* worked well," observed Ranma at last.

This struck me as extremely funny, that Ranma and Akane would wait
up without having any kind of a plan other than just asking for the
film.

Anyway, great fic.