Some of us probably need to get over what we think an "expo" should be (me included), and go for the best reasons like meeting other pinheads. I would in no way call this an expo, but its an opportunity for the hobby none-the-less.
 

Someone has to pay or the costs of running the Expo. Sponsors and the Auction will assist in this area.

Lets say there is no Auction - Costs will be covered by sponsors and ??  So to recoup costs, I assume the organizers would be forced into having an entrance fee. Then there is the possibility of backlash for the entrance fee ?

For the record - I've stated I'm not a fan of Auctions in general, but it is a necessary "Evil" in this case.