> There only real risk is that maybe by some huge stroke of bad luck, some other plant (a weed, say) picks up glyphosate resistance from these genes

Well, I'm glad we have you to think through every single possible chemical, biological interaction between a genetically modified plant and the rest of the environment, which we humans understand and can model perfectly. Complex coupled system dynamics ... easy for jeffmeden! Of course we can predict all the consequences of our actions, especially when applied on an industrial / global scale in a short few years. Why worry that there may be something that we haven't thought of which will manifest itself in a generation or two. After all, it's only the world's food supply and our life support system (the environment) that we're talking about here. If by some astronomically unlikely chance we've made a mistake we can just hit the reset button and try again. There is a reset button on the Earth, right?

Because 36,000km is where geostationary orbit is ... the elevator is tied to the surface of the earth, and so makes one rotation per day. You *could* get off at 360km, but you'd be moving waaay below orbital speed and would fall straight (actually elliptically) back to earth. No chance of docking with the ISS, which makes an orbit approx every 90 minutes IIRC.