It would be dumb of the defense to not notice and respond to the 1st situation, also. And if the defense simply does not notice the double runners and the pitcher is looking to toe the pitcher's plate and start the next pitch, what do you do? That case play doesn't address it and there would be a significantly different impact of advancing a runner vs. moving a runner back.Now you have a different situation, you have a forced runner that must be put out or the play is not over. It would be rather dumb of the defense to not play the force at 3rd base with the runner still standing on 2nd.