I find it very interesting that at the Emory info session yesterday, they mentioned they review all applications regardless of signalling. They then said "in our review, we found most of our interviews go to candidates who signal." However, the way they said it made it seem like they still seriously consider your application if you don't signal. I wonder if this association they find with signaling is actually biased, i.e., the candidates with ties to Emory or with stronger mission fits are more inclined to signal (and thus have a higher interview rate).