At the end of the day it still comes to the players' mentality and how they perceive the game. It's actually pretty simple imo, players that play the game casually and are not "dedicated" to the game will only attend events that will offer some sort of freebie (be it a lucky draw, or signup goodie bag) Whereas on the other hand, the ones that are dedicated to starcraft 2 ( they do not necessarily have to be good in the game ) will try their best to join ANY starcraft 2 event, as long as the event is accessible to them.

So now the big question is, how many people out there are TRULY into Starcraft 2? I guess heavy promotion and frequent SC2 related events will act as a catalyst to encourage more dedicated players.