"Then you notice your car keys have moved from where you last left them (maybe you're misremembering, or your DC moved them etc)"
You really, really don't understand what disappearing object phenomenon is, do you? It isn't misremembering where you put something. It's checking a particular place for an item, e.g. a table, even more specifically, a particular spot on that table. The item isn't there. You're alone in the house, with no other people, children, pets, anything else, with you. Just you. You know that item isn't on that table, because you just looked, with your eyes, and felt, with your own hands, and it. is. not. there.
So you leave the room, or even just turn your back to look elsewhere, just for a minute, maybe less. Then you reenter the room, or turn back around, and that item is there, in that exact spot that you'd checked, a minute or so ago.
You near jump out of your skin, because how the fuck could that have happened? It can't happen. It's not possible. And yet it just did.
That is disappearing object phenomenon. Anyone who, like myself, has actually experienced it, will know what I'm talking about. You clearly haven't, so you really don't.