@michaelHarvey Well that just seems silly. Forms requiring BLACK ink generally require it for photocopying purposes. If someone knew this, and used a dark blue that they knew would photocopy well, they would have independently used their own knowledge to find a good solution to the problem - yet be instantly rejected. If it's not about photocopying, that should be tested explicitly ("Complete this form with a BLACK ball point pen or it will be rejected - this is a test of your ability to follow this instruction"); right now, some smart, knowledgable candidates are being filtered out.

As J... says, the experiment is incomplete. I was typing out something similar, but J... beat me to it :) If the 47 rejected candidates contain applicants who are serious and detail-oriented, then the filter is ineffective and in fact is filtering out the very candidates you want to keep in the pile.