In a house I used to live in, over in Hemel Hempstead, I once found a very rusty key on the pavement outside, some distance down the street, and when I checked it, it turned out to be the key for my front door!
Both myself and my (then) missus were the only people who had keys, and it was a house we had bought some 3 years previously, and neither of us had ever lost a key.
That pavement was one I walked everyday for a couple of years too, in a nice area, with regular cleaning & litter picking, and the key I found was just in plain view in the middle of the pavement.
Now that did strike me as peculiar yet I attributed it to JOOTT.