yeah the John Deere repair fiasco is a lot like Micro-shaft using "software audits" to punish their own customers. when you treat your customers poorly, they'll find ways around you, if they can't (for some reason) get a competing product and tell you to pack sand.
It's the first thing I thought of when I saw the title, the use of DRM to prevent farmers from working on their own tractors. I could see preventing amateur mechanics from working on their own cars as "the next step".
Still, legislation and/or bureaucratic action to create exceptions like this is _STILL_ lipstick on the non-oinky end of the boar. it does NOT fix the fundamental flaws in that stupid 'digital millenium copyright bullshit' law.