Jon,
Brain storming is an art. There are times when they become out of control if not handeled correctly.I was part of a brain storming group with teacher negotiations once where there were about 16 people involved. The person facilitating had some requirements we followed. As we went around the room each person would only talk when they had something to contribute. There were timelimits on people to speak and people could pass. After exhausting the suggestions there was a break. After returning Comments would be called upon when someone would ask to be acknowledged. The next meeting there were four teams created with the suggestions and issues given to each team. Solutions were discussed by each team for reporting.
I think you see the process is very organized with full capability for everyone to become involved.