> DRM can only protect information not the operation of a physical device.

So I think it would actually be reasonable for the DRM to protect a physical device; but the contract should be structured as such.

If I have title to my car and can dispose of it as I see fit; I shouldn't have to abide by DRM. If it is rented and doesn't actually belong to me, then I could see technological mechanisms such as limiting mileage or range as a valid way to enforce part of the contract.

What the line of appropriate vs. not appropriate is of course not necessarily black and white; but I do think John Deere is in the wrong here and the farmer is in the right.