The performances were outdoors, at The Avenue at White Marsh, a sort of upscale fake-old-downtown shopping center. The acoustics were better than we were afraid of, although some sound did tend to get lost just going up into thin air - no shell to reflect sound. The shopping center management turned the fountain off so that we didn't have the water sound white-noising out our playing. On the other hand, about midway through the afternoon, every Harley Davidson in a tri-county area decided to use the parking lot around the outside of the center to tune up, and kept it up for a couple of hours. Luckily, Bel Air, at least, is a large enough band to drown them out. I think Bel Air was the largest group there, though I didn't count heads for everything. Being outdoors also meant sunburn - one tends not to realize what odd parts of one's arms and ears get exposed when holding a large instrument, watching a conductor, moving around the clothespins that were holding all the music, etc. (One of the skills they don't teach you in college: how to deal with outdoor music that isn't on marching lyres.)
As far as I could tell, coordination among groups was good enough that there were no duplicates in any of the programs. Of course outdoor music will always be heavy on marches and musical, or Sousa and show tunes if you prefer that alliteration. Montgomery Village did music from "Pirates of the Caribbean" for example, which of course I enjoyed because it's got a couple of genu-wine bari sax solos, played by yours truly. But we also did "March and Procession of Bacchus" by DeLibes, a fairly good transcription. And Bel Air (in which I play tenor rather than bari sax) did music from "The Incredibles" which was great fun, and very popular with the audience - it combines all the cheesiest aspects of Get Smart, James Bond, and Batman. We also did a "Fantasy on 'When Johnny Comes Marching Home'" with a piccolo soloist, and frankly, I feel that that was a mistake outdoors; the piccolo was nigh inaudible, even with a microphone, because it was just a mike on a stand placed near her, not one that could be clipped on, and it wasn't that great a mike.
My spouse and I missed Olney, as we went to eat dinner with relatives who had come to hear us play, but we were back in time to hear Baltimore play. They closed things up with some good numbers, including Camphouse's thingy for Rosa Parks (can you tell that I am too lazy to get up and get the exact title, and also going crazy itching at my sunburn?)
I'm not sure about 2007, but Montgomery Village has requested the honor of hosting the event for 2008, and, assuming I'm still alive and kicking, I will be band president for that one. So I am taking notes already to add to the "what to do and how to do it right" list!