From what we're shown in the story, magic use in the corridors (as distinct from dorms, private study sessions etc.) seems primarily related to bullying. There are people using utility charms in the corridors (e.g. Harry part-Hovering an exhausted Hermione), but we don't actually see this happen very often at all, whereas bullying is apparently frequent and endemic.
Really, this makes sense. Given that there is a ban on magic in corridors, you would expect bullies to ignore it much more often than law-abiding students.
Edit: Putting it another way, suppose we live in a world in which Dumbledore is concerned about the bullying problem and wishes to use his influence as headmaster to combat it (insofar as he can do so without ending up in a confrontation with influential parents). In this world, would you predict that Dumbledore would dismiss Filch's reminder in front of the whole school?
New long chapter! Since I expect its discussion to generate more than 160 comments (which would push the previous thread over the 500 comment limit) before the next chapter is posted, here is a new thread.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 108
(and chapter 109, once it comes out on Monday).EDIT: There have now been two separate calls for having one thread per chapter, along with a poll in this thread. If the poll in this thread indicates a majority preference for one thread per chapter by Monday, I will edit this post to make it for chapter 108 only. In that case a new thread for chapter 109 should be posted by whoever gets a chance and wants to after the chapter is released.
EDIT 2: The poll indicates a large majority (currently 78%) in favor of one thread per chapter. This post has been edited accordingly.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: