I lived in North Dakota for 11 years, for 6 of those years in small farming towns surrounded by vast flat crop acreage, literally stretching to the horizon & beyond. And those fields had signs posted along the roads, that said where the seeds for those crops had come.
Many of them were from Cargill, and Cargill inspectors would go into the fields and take samples for genetic testing. If a farmer had a crop that showed a unique Cargill genetic trace, but had not bought the seed for that year's growing season, he'd be given an option: pay a penalty and keep his crop, or have the crop destroyed.
That's because a farmer might have used his previous year's crop to harvest some of the seed for this year's crop. In past years a farmer could ordinarily do that, if the original seeds had not come from Cargill. But the company retains the rights to the seeds forever, forcing farmers to buy new from Cargill every year.
I have mixed feelings about this. Many of these crops were in fact genetically engineered, for such qualities as insect & disease resistance, and also size. But what exactly did the farmer buy, or is this merely a rental? Should Cargill own the harvest, too?
For instance, did you know that modern wheat is engineered to be very short in height, not the tall stalks you see in movies? With modern combines, versus older equipment, and even manual scythes, it's possible to have a short shaft.
The short shaft consumes less of the plant's growing energy, matures quicker, and is less prone to wind damage. Because all you care about is the head where the kernels are. So today's wheat has been engineered, as have many of our plants in the US.
I'm therefore not sure what the issue here is in Belgium. Engineering has become the standard in the world. I see it little different from the hybrids that have been developed over centuries past.