I'm basically proposing a principle that could be cast into law. Plant a crop with IP attached to it, then you better clean up after yourself. Monsanto would probably lobby against such a law, but so what, screw them and pass it anyway.

I'm pretty sanguine about the teetering. Among other things, companies like Monsanto (and thus their competitors) like to do things like maintain big seed banks. So do academics and hobbyists.