I agree with all of the above. I guess for some reason I am doubting the implicit impact that meeting with the staff might/could have on a subsequent evaluation of your application. For instance, I'm pretty sure there are some attributions made to applications from familiar sources (ie, students of colleagues, classmates of current interns, etc) that may not be made without some of these associations (in some cases negative as well). I know they say it won't have any impact, and they probably try to do that, and in some cases succeed. But.. I suppose I have my doubts. It's like a jury disregarding information they weren't supposed to hear. Do they really?
I appreciate any thoughts. For the record, I only have one open house and they say attendance does not impact ranking (however, ranking is reportedly not solidified until well after the open house). I am going to attend, because I want to be able to see if they are a good fit for me anyhow. But my question lingers...