I have not been to a NAM, but I have been to an ALL HANDS conference, which every BSA professional was required to attend. It was a mix of information sessions, speakers, and socializing. While they did give everyone a copy of the scripts used by the presenters for all session, some presenters had a lot experience on the topics and was able to give info beyond the script in Q&A sessions. Some presenters strictly followed the scripts they were given.
In today's age of technology, it may have been better to do it as a teleconference and recordings..