hmm mixed feelings about this one!! while this could be good for things like what you mentioned, it also lets people who make dreamie folders or fav4fav folders put characters in them that the owners aren’t okay with being put in there. I think if this feature is implemented it should still allow the original designer and current owner to see where their character has been placed, though then that lets them see every other character in that folder so hmm, it’s kinda messy.
I think an okay temp. solution to this could be labelling your folders confusingly or ambiguously so that people don’t know why the characters are there. maybe put a few red herrings in there too, or split the characters into multiple different folders, or put them inside larger folders so they are harder to get to. :] though a lot of these half-solutions come at the cost of organisation so it’s definitely not ideal!!