For what it's worth, I think that report may have softened the detail a little. The trial court's opinion says:
"A farmer whose field contains seed or plants originating from seed spilled into them, or blown as seed, in swathes from a neighbour's land or even growing from germination by pollen carried into his field from elsewhere by insects, birds, or by the wind, may own the seed or plants on his land even if he did not set about to plant them. He does not, however, own the right to the use of the patented gene, or of the seed or plant containing the patented gene or cell."
So, the question of the right to allow the Roundup Ready plants to grow hinged on the fact that they were patented, not on the mere fact that they were GMOs. That line of reasoning is a response to the farmer's defense argument that the seed drift caused Monsanto to waive whatever patent rights it has. That in turn is part of the larger attack on the patent's validity.
The flavor of the opinion that I get is that the judge believed the farmer knew that some of the crop was Roundup resistant. There was no jury in the case, so the judge ruled on both the evidence and the law. I probably am biased, and I certainly was not present to hear the evidence, but I question whether Monsanto met its burden of proving patent infringement. Because of the level of deference usually given to evidentiary findings, it might be hard for the Canada Supreme Court to overturn on the trial court's evidence rulings. Whether the Supreme Court will reverse on the law or remand for a new trial are different questions. Even if the decision is upheld on the law, it seems to me to reflect very poor policy. Whether the farmer can prevail in his action against Monsanto for destroying his breeding line of canola with seed drift is an interesting question.