I doubt the Ch. 6 signal was magic, since he'd invented it and the recognition code before knowing about magic, and implemented during his first shopping trip. I don't think you'd need magic to signal obliviation or a full-on groundhog day attack.
Oh, I agree. I speak of upgrades to his precaution measures which I would expect him to have by now.
Magic-wise, I'd suppose that obliviation would make a rememberall signal permanently, but then it seems like that would be important to for obliviators to counter somehow.
Your point regarding countermeasures is important. Particularly savvy wizards can be expected to think of that. For this reason I would expect harry to maintain his mundane tactics as well. This exploits the known blind spot of nearly all non-Quirrell wizards. Improving his mundane signalling system has also been raised in importance now that Harry is aware of the possibility of Obliviation and has more reason to expect enemies to be motivated to use it.
Magic leaves an armory worth of potential Chekov guns laying around. If owling hand grenades isn't enough to win the next war, it should be something interesting.
An example being the money earning scheme. I would probably enjoy reading about other tactics that Harry considers even if they do not end up being Chekov guns!
Magic-wise, I'd suppose that obliviation would make a rememberall signal permanently, but then it seems like that would be important to for obliviators to counter somehow.
This was brought up before:
"More importantly, why did the Remembrall go off like that?" Harry said. "Does it mean I've been Obliviated?"
"That puzzles me as well," Professor McGonagall said slowly. "If it were that simple, I would think that the courts would use Remembralls, and they do not. I shall look into it, Mr. Potter."
Of course, there ...
Update: Discussion has moved on to a new thread.
The hiatus is over with today's publication of chapter 73, and the previous thread is approaching the 500-comment threshold, so let's start a new Harry Potter and the Methods of Rationality discussion thread. This is the place to discuss Eliezer Yudkowsky's Harry Potter fanfic and anything related to it.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven. The fanfiction.net author page is the central location for information about updates and links to HPMOR-related goodies, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
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: