Kim:... The idea was very simple, it's a lot easier for the manufacturers to talk to their distributers/retailers when the whole place isn't also clogged with consumers. Remember - this is serious for them as they are taking large orders for new product, and often setting out order patterns/strategy for the next year....
I went to DEMA last year as a dive store employee (I'm a divemaster and help with classes and local dive trips). Since my name tag did not say "Buyer", many booths wouldn't pay much attention to me. DEMA is primarily a place for the manufacturers to connect with the distributors/shops.
But don't give up! There are great dive shows for the public. Pick one and go. I'll bet they're just as good if not better than DEMA.