All keyed up

Nikki found our old house keys this afternoon.

Out for a smoke in the front garden, she saw something glistening in the bushes. The full set, still on its Indian-bead-and-bell keyring. After we forked out £250 to have all the locks changed (insert wry smile and rolling of the eyes here).

No sign of the other two sets though. Which begs some questions:

1. Were they dropped as the tw@s made their getaway on Thursday morning, and have been lying there ever since?
2. If (1) is true and we'd found them earlier, would we have felt safe not changing the locks?
3. Were they discarded more recently, after said tw@s had returned to try them in the door?
4. If (3) is true, how did they know the set they threw away would have been the right set?

It's all very mysterious. Not to mention irritating. Nice to have the keyring back though. I missed its tinkly little bell. Make no mistake though...we won't be keeping any keys on a rack by the door from now on.