There are zillions of moderation practices like that one. They all appear repeatedly in my moderation comments, often with search links that point to past examples. But we don't make a formal list, for a bunch of reasons. One is that it would make the guidelines so long that no one would read them. Another is that we're not bureaucrats. A third is that if you make a list of everything, people will conclude that if something is not on the list, it must be ok, and that's not at all how HN works. It has always been a spirit-of-the-law, not a letter-of-the-law place.