When asked why it was standing in the way of farmers who want to fix their own tractors, the company replied that farmers didn’t really own their tractors. According to John Deere [PDF], farmers have only “an implied license for the life of the vehicle to operate the vehicle,” and farmers (or their mechanics) aren’t allowed to fiddle with the software to effect a repair.
Naturally, that position upset a lot of farmers, who assumed that when they plopped down $75,000 or more for a new tractor, they were buying the whole thing. They felt they should be able to fix their tractors on their own terms. And it turns out that the farmers were right.