Board Thread:Warhammer 40k General Discussion/@comment-2253300-20130211000751/@comment-66.120.29.153-20130411013442

I always thought that was more about keeping the existence of the Grey Knights secret rather than covering up the existence of Chaos. I know there is one specific instance in which the Space Wolves were allowed to keep their memories intact rather than having those memories erased, but it wasn't because they fought Chaos, it was because they fought alongside the Grey Knights.. Every Space Marine chapters is allowed to walk around with knowledge of Chaos, so it implies that those mind wipes were about the grey knights, not Chaos itself.

I can't see the Grey Knights constantly running around with MIB flashy thingies wiping people's memories, there's only a thousand of them and it'd take a year of potential demon hunting time just to clean up after a Black Crusade. Not to mention that everyone that serves at the Cadian Gate would lose years of their memories as they are there specifically to guard the Eye of Terror.There might conceivably be an administorum whose entire job is to just wipe people's memories constantly. But then you're degrading the effectiveness of your army as the IG who fight Chaos must overcome their initial fear and develop tactics every time they battle Chaos as they will never learn from experience.