I would say that most crossovers are opt in. If the canon has crossovers in it, then I think doing things in line with that would be fine (e.g. Abed from Community appearing in the background in a Cougar Town fic). If the person didn’t request the second fandom, I probably wouldn’t do it.
Re: very minor crossovers
(Anonymous) 2024-12-11 03:59 pm (UTC)(link)