Register for the event at the organizations member rate
Our membership is based on organizations, not individuals and the memberships of these organizations is transitory, thus using email address as the identifier for an organization will be a real problem.
This becomes an even bigger headache when setting up an event (convention) where there are multiple people registering from the same organization. When they are prompted for an email address, they are going to enter THEIR email address, not that of the person who joined our organization on behalf of theirs, particularly if that person is no longer a part of that organization.
What I have seen that works is a system that requires the first three of a zip code. Once entered, the application returns a list of members in that area. Keep in mind, this is for event registration, not membership.
Once the person using the application self-identifies as a member, they can register for the event at the organizations member rate. That can't happen with Wild Apricot. Before we spend any more money with your company, we would like to see this fixed.
That's a good point but not something we can not change soon.
See also http://forums.wildapricot.com/forums/308932-wishlist/suggestions/8825890-enhancements-for-registering-a-group-of-people-e (Handling team registrations)
Buy the way, would bundles work for you? I mean that organization can be "bundle admin" while all real members are "bundle members". In this case, you can create special event registration type for bundle level.