First, let me say that I am NOT
speaking for KCBS on this - only for myself as an experienced judge.
KCBS has absolutely nothing to do with how judges are selected or where they sit. These are strictly up to each individual organizer and each one can do it his/her own way.
Some organizers go on a straight "first come - first served" basis. Some use only Certified BBQ Judges, some use their friends, celebrity judges, lodge members, etc. Some use the same judges every year and the only way to get a seat is if some one drops out.
Most organizers use a combination of the above methods for selecting their judges.
Most organizers also keep a list of judges that they have had trouble with in the past - try not to be on that list
The KCBS Contest Rep is there to enforce the rules and to make sure that the contest runs smoothly and fairly for all concerned.