If I understand the article, this is not a case of interbreeding, but a case in which a dealer (or the farmer) mixed seeds from Roundup Ready plants with other seeds. The contractual requirements for using and selling Roundup Ready seeds have been around for close to 2 decades at this point, and are well known to the entire agricultural business. Considering the hundreds of thousands of farms that use GMO seeds, it's not surprising that there are a few cases of farmers who think they can violate the patent limits. There is at least one former farmer who grew his own Roundup Ready seeds from plants that were seeded on his property by wind or neighboring spill, and was caught and sued by Monsanto. After looking carefully at the evidence, the court found that it was clear that the farmer had knowingly violated the rights of the patent-holder. He's a hero to the anti-GMO crowd now. Whether this case will be that simple is not for me to say, but I doubt that the Scotus will overturn the idea of GMO patenting at this point.
I find the hysteria over genetic modification to be just that -- arguments based on ignorance and anger, turning a fairly humdrum technology into a science fiction novel full of spurious arguments about non-issues.
Just to take one example: The opponents make a big deal about the fact that there is a small bit of DNA in Roundup Ready plants and BT resistant plants that you eat, along with all the other plant DNA, when you eat the corn or the vegetables. You eat a lot of DNA all the time -- we call it good nutrition -- and your body recycles the subunits. We do the same thing with vitamins, minerals, and proteins, just to name a few other nutrients. At the same time, we also eat a lot of microorganisms that carry the same genes the anti-GMO people are so hysterical about, and we eat them in their full-bore natural hosts such as the soil bacteria from which they were originally identified. We've been doing this for close to 20 years, and there is no evidence of harm, but a lot of evidence that it saves farmers money and reduces the amount of herbicide that gets sprayed.
There is a "study" that has just been revealed by a European lab that purports to show that Roundup Ready feed is carcinogenic to rats. The study is so bad that serious scientists have blown the whistle on it -- the least of the complaints is that when you take the study's data and subject it to standard statistical tests, the result is that there is no result. The authors therefore had to make up their own statistical methods, so to speak, in order to claim results. One wag pointed out that it would be akin to dealing yourself 2 cards, and dealing your friends 5 cards each. Then, you turn over the cards and show that one of your friends has more hearts in his hand than in yours, and if you look hard enough, you can find another friend's hand that has more diamonds. In other words, when you grow a small number of rats which get tumors 80 percent of the time if they live long enough, and you let them live long enough, you see tumors. If you limit the control group to 10 rats and do various test groups of 10 rats (they really did this!), you are going to see random variations in one group or another, which is exactly what they found.
The analogous experiment you can do is to take 10 nickels or 10 quarters (it doesn't matter which) and throw them into the air. Count the number of heads and tails for that throw and write it down. The average for a lot of such throws is about 5 heads and 5 tails, but in any one throw, you may get 3 of one and 7 of the other, or 4 vs 6, and so forth. That's what the European study did in effect, but I have been reading letters to the editor in my local rag that quotes this study and claims that GMO corn causes huge tumors in rats.