@d3vy
Regardless of what they're doing with the GM seeds to avoid their reuse, nearby farmers sometimes end up with the special properties of the GM seeds getting bred into their seeds.
There was a famous case in Canada where a farmer who lived next to a farmer using Monsanto GM seeds that were RoundUp (herbicide) resistant blew onto his field or managed to pass that trait to some of his normal seeds. He noticed this and collected those seeds and bred them through traditional methods, and Monsanto sued. Their argument was that it wasn't that he accidentally got the RoundUp resistance trait in a few of his plants, but that he specifically collected the seeds that had acquired that trait and bred for it to get their patented capability for free.