Thx, Atlantis, you've come through again!
SBF, one observation:
"the GB’s status ... is a position for life."
Not exactly. It's for life only if a member does not fall into disfavor with his most elite peers: witness Ray Franz, Leo Greenlees, E. Chitty.
As for appeal committees overturning a local committee's decision, I know of only two. It IS quite rare.