I'm not sure how those things would be related. The above post is about ensuring that the markings given to the model along with the text about the prompt/data

I'm not sure how those things would be related. The above post is about ensuring that the markings given to the model along with the text about the prompt/data distinction are "out-of-band", reliable, and can't be influenced or faked by user-controlled data. Having the model actually act in accordance to the prompt is a wholly different issue; but at least this discussion seems to assume that this is mostly solved (e.g. by reinforcement learning from human feedback) and that the main problem is the injection itself.