Thank you so much for finding that video and looking into this for me! I'm looking into all of this for a friend and her island has 600+ hours so I'm trying to be as thorough as possible and understand all the risks.Will take a look. I was speaking more to the practices of JKSV and CFW that folks typically ask about. Each of the things we’re talking about alone won’t get you banned but I see where the change of save file status for a particular switch with this particular game might get you flagged.
E: This looks like the right one:
I see the comment where it’s asked and answered that ACNH saves are watched ”like a hawk”.
Here’s a thread talking about doing pretty much what we’re discussing and there are some folks that say it’s fine as long as you don’t edit and others that say you’ll get flagged.
I would think that they watch for people cheating ”like a Hawk” but maybe since this is a system level save rather than a profile save they flag any changes whatsoever?
I’d confirm this specific use case in the banning hub thread to be more safe.
I've read a lot about people warning against save edits as well. But wouldn't injecting a different save look like one huge edit?
I've looked through the ban hub thread that you linked to and haven't found too much about Animal Crossing. And nothing about only keeping multiple islands. I'm assuming that's a good sign.
One last question (I hope I can ask this clearly): If I were to inject and play a second save only while completely offline, then restore to my old save anytime I wasn't using my second save, would this be the safest course of action? Or would the Switch's telemetry pick up on it anyway?