John Deere bought out the only company that was really producing aftermarket parts a couple of years ago, so that's a non-issue for them.

As an aside, I had the JD tech out to work on my combine a while back. I watched him have to decrypt the service manual on his computer before he could use it. I was somewhat amazed at the lengths they go to to protect their information.

Almost. Once he unlocked it, he handed his computer to me and let me poke around freely. Hard to put a complete stop to social engineering.