My reading of the visa thing was that the Auror made it up on the spot to confirm that Quirrell had no idea of what trips he had taken in the past, and is therefore an impostor. Although I don't understand why Quirrell, if impersonating someone, would fail to look up these simple facts.
Quirrell is smart, but he's not omnipotent. He's had so many lives, he doesn't even consider any of them to be his true persona.
Quirrell is mentally disciplined, but it's possible that he could have simply forgotten or gotten facts mixed up, trying to hold so many personas in his head at one time.
(The HPMOR discussion thread after this one is here.)
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. There haven't been any chapters recently, but it looks like there are a bunch in the pipeline and the old thread is nearing 700 comments. The latest chapter as of 7th March 2012 is Ch. 77.
There is now 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.
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, eight, nine.
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: