I know Mike and Chuck (2 of the IWM Booth workers) travel from VA to work Gen Con. I think they work Origins and Historicon as well. They have "Day Jobs" they have to take time off for for those Cons, so that probably limits them on what Conventions they can work. I know Speck works GC, but I'm not sure where he lives, or if he makes the other Conventions or not. :-\
I'm Guessing that "Booth Help/Worker Availability" is a HUGE part of the Factor for what Conventions IWM and CGL attend.
Imagine Gen Con without the Demo Agents! :o Sure, I think CGL pays for their badges and lodging, but they have to travel their on their own dime. I know a few come from Canada, and some Probably come from each Coast as well. Travel costs aren't cheap, but the CGL Volunteers do it because they Love it!
I've "Bumped Heads" with some of them a time or two online, but I'm GLAD they volunteer at Gen Con! :thumbsup: :clap: :clap: