Well, obviously you guys have not run at Huntsville State Park. The majority of the trails are single-track and in past experiences while competing for the individual title, many lead runners come up on athletes wearing IPods and you can't get around them for a few seconds because they are listening to music. It is a huge annoyance, especially if one is going for a personal best or a national-leading performance, etc.
Just from personal experience, but I would hate to be one of the favorites, in a rhythm, get stuck behind a train of IPod-listening runners unable to move out in time and disrupt the pace of the elites.
Good call on part of the RD. Guys, train solo with music, but in a race setting, leave them at home. I train with an IPod, but no way would I race with one.