It is indeed. However, they "volunteered" by having won the Uniform Competition.
Policy is that if you win, you have to be a judge once before you can compete again.
I haven't seen anything on who won at the 2006 Muster, but I know Jack didn't judge at that one, so he still has to pay up.
If Drydock judged at the 2006, he is discharged from this duty. If not, he is volunteered to be a judge.
Policy is also that you can't wear the winning uniform in any other Grand Muster uniform competion, though you can always enter in another uniform after you've served the following year as a judge.
US Scout
GAF, Commanding