Hypatia, that quote by AC Pfeffer actually sounds pretty much the way it'd have worked, with an ghost of the item still appearing on the avatar it was attached to originally, then just saying it isn't possible to rez that item and eventually disappearing from the inventory after clearing cache.
Guess I'll go over to not wearing any no copy attachments.
Hey Beez!
Edit says: Actually, I'm not having any proof for it, but I inspected one of the custom made items that disappeared from my friend's inventory, of which only two copies existed, while it was on the avatar that stole (Yup. There we go.) our items: Her's and the creator's.
When I inspected it, it still was showing the original creator. -> No "copybot", but rather the issue AC Pfeffer was talking about.
Case closed, I guess.