If that were so, then it would have made detecting Imperiused infiltrators during the war trivial: just floo everyone in the Ministry through a room in Hogwarts, with in- and out-fireplaces, and arrest any who set off the wards. You could do it once a week, or every morning, or randomly thrice a week, or whatever. It's too obvious, and too easy and non-controversial, for someone like Dumbledore not to have noticed and put in place. This did not happen.
The ministry was clearly not actually trying to catch Death Eaters during the first war. Even simpler than this (as a first pass to catch spies) would be to make all ministry employees roll up their left sleeve on a regular basis.
(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: