(By the way, my own answer to Will’s question, in effect, is on p. 140 of my anthology chapter.)
The Molinari Symposium will be held in Independence Meeting Room II. (The APA program supplement says “Independence Ballroom II” but there is no such animal; the Independence Meeting Rooms are next to the Liberty Ballroom.)
Independence Meeting Room II is hard to find because it’s actually across the street (via skybridge) from the main hotel, in something called the “Deluxe Tower” (or, less glamorously, the “3rd Floor Annex”).
How to find Independence Meeting Room II: from the hotel lobby (1st floor), take the escalator (not the elevator) to the 3rd floor. (It goes directly from 1st to 3rd; I’m not sure there even is a 2nd floor.) Follow the signs that say “Deluxe Tower” or “Bridge to Convention Center.” Cross the skybridge; at the other end you’ll see an arrow pointing left saying “Convention Center” and an arrow pointing right saying “Marriott”; go right.