I'd say that most will find the cost of travelling and participating a barrier, how many people here don't even live in the US?
Why not run a live web televised seminar and charge people for access, seems to solve logistic and financial concerns and surely would be more profitable.
Would you pay $40 for a two day web seminar from the comfort of your own home or $1000 min. to get to LV?
People are going to buy the DVD of the event anyway.