Who stole my plums? That's what I'd like to know. And why didn't you just ask?
That's what people do - have a few manners. Open the gate, go to the door and knock.
"Hello there. I'm just passing and notice you have a lot of plums. I'm wondering if you'd mind me picking a few for my poor family. I'll make some jam/pickle and bring you a jar."
No - too easy. That didn't happen. Whoever nicked the whole tree full of ripe, juicy plums - in broad daylight I might add - did not bother to use their manners.
I say broad daylight for a couple of Sherlock Holmes-esk reasons. If the robbery took place under cover of darkness, firstly the porch light would have come on and secondly, they would have undoubtedly dropped a few and not been able to see them.