I assume you are referring to the fact that the traits can make their way into non-GMO seeds due to the way nature functions? However, Monsanto has only been able to successfully defend their patents when gross violations have occurred – i.e. the crop has also been sprayed with roundup. Someone who is honestly trying to grow non-RR seed is obviously not going to be doing that.

Monsanto has been so successful with this because, for 99% of the farmers out there, these patents have no effect on their business. It wasn't particularly common to grow your own seeds for a variety of reasons, even before the patents came into effect.

I suggest you read actual peer-review scientific journal articles on the matter instead of relying on a documentary you saw on NetFlix.