The event must be VERY well organized. No maybes, but lots of leadership. On the otherhand, the leaders need to prepare for flexibility. I think club logos and NCTA logos should be everywhere. People need to know who's responsible and that there is an organization standing behind the event.
Introductions are a minimum.
Name tags help at some events. Not all people have e-mail, read web pages, pay attention to the newsletter, etc. Nothing works better than the personal phone call. At a minimum, they should be on our mailing lists.