These prices are not related to unions. It's because convention facilities and trade show producers are in business in order to make a profit, as they well should be. Supply and demand and all that. ;-)

I have attended many trade shows, conventions, etc. Companies know it costs an arm and a leg to exhibit at the big ones and they do it because it is a necessary part of keeping up important business relationships, not only with press contacts, but retailers, wholesalers, foreign licensees, etc.

And a show like E3 is a great venue to unveil upcoming titles and begin seeding awareness among consumers.