That antagonistic behavior being what? I ask because there's a commonly-held belief about Monsanto that they, in effect, wait for the wind to blow IP-encumbered seeds onto fields and then sue the farmers who manage those fields for royalties.

The reality is that Monsanto sues farmers when they take Roundup-Ready crops, plant them, and then use Roundup on those crops. You can't do that innocently; if you spray Roundup on non-Monsanto crops, you kill the crop.

If there's a case where Monsanto sued a farmer simply for having Roundup-Ready seeds or plants on their farms, I haven't seen it, and I've (a) looked and (b) asked around a lot.

If you just mean that patent enforcement is inherently scummy and antagonistic, well, I have no snappy response for that. Although again note that the problem with software patents is that you can implement some obvious piece of functionality and get sued by someone with a ridiculous patent. Like I said, nobody accidentally uses the whole Roundup system on a farm.