The presentation adapts itself, but the content is either the same or written in an inverted pyramid style so you can chop it off at some level and still have the remaining content fit together. The content is as important as the producer and recipient. Rules like that could end up in the guidelines. People have issues with creating hard and fast rules if you put something in where you don't give content producer some way of saying what I've done is better than what I had before because it satisfies the guidelines. The concern is that the content itself has to be figured in.
Rules have to be contextual.
If you are looking at a document to decide whether to comply with this or not, if you aren't sure you can actually help with this particular content, it makes it harder to embrace this goal. I think it should. It should be. It will be left up to what is used in educational circles. We must say it is intended for X level.