That's a deliberately flawed analogy. You don't copy the DVDs. The DVDs copy themselves, using your land and resources to do so.
This is more like somebody "accidentally" setting up a DVD pressing factory on your property. You quietly let the factory owner continue pressing DVDs (using your electricity no less) and sell the DVDs yourself when they're ready. It's all on your property, the factory owner is trespassing and I don't see how the factory owner can claim a right to the pressed DVDs. (Don't build automated self-reproducing things that you want to claim patents on, even when they're stealing other people's resources.)
This is more like somebody "accidentally" setting up a DVD pressing factory on your property. You quietly let the factory owner continue pressing DVDs (using your electricity no less) and sell the DVDs yourself when they're ready. It's all on your property, the factory owner is trespassing and I don't see how the factory owner can claim a right to the pressed DVDs. (Don't build automated self-reproducing things that you want to claim patents on, even when they're stealing other people's resources.)