All of those first three are available to any enthusiastic Schmoe who shows up at a BBQ festival. Obviously the social aspects of the community are a plus for all involved.
I spoke directly to the tangible rewards offered to judges vs. cooks. As for the "powers" you endow judges with, consider the following:
The average judge is considerably older than the average cook, and often retired.
Cooks can be a boisterous lot on Friday night, and judges are instructed to stay away from teams on Saturday. Combine that with the judge-bashing prevalent in the various BBQ forums and the smack talk some like to engage in, and interacting with the cooks must seem intimidating to Mr & Ms AARP.
I can give you one concrete example of this - at the current contest I organize, we distribute all the goodie bags to the teams. Each team gets two bags: one to keep and one for a judge. When judging is completed, each CBJ draws a team from a hat to go out and chat with and claim their bag. It's a program designed to break down the barriers between cooks and judges, and almost universally well received.
But not totally accepted, because every year I speak with at least one team who tells me their judge never arrived. This puzzles me. It's not that they aren't physically able to get there, we give bags directly to those with mobility issues. It's not that they can't find the team as I show each where the team is on a park map and describe their rig. All I can figure is there are a handful of folks in every group who are just painfully shy about meeting with cooks and would rather abandon their swag than walk into a team's camp and say hi.
I don't know what else I can do other than pass out Powdermilk Biscuits in the judging tent.