Omaigat, Matrix has us.
Maybe not just use same as captcha as in browsers and be a bit creative?
If we will follow your logic and people will go to the lengths of using machine learning algorithms in order to make themselves some space peso in Elite, what hope do we have? For how long not having autopilot in-game at all would barricade them? 3 days of machine learning? We can do at least some small things, like, I don't know... decrease demand for them a bit. By adding legitimate in-game autopilot.
So now the new autopilot, added so that players don’t actually have to fly their space ships, is now diverting even more development resources away from adding new environments in which to not fly their spaceships in, to deal with the problems created by it in the first place? Maybe FD should just quit developing Elite Dangerous, and go into the captcha development business.