arbiter

“Arbiter” is the English word for an entity that “settles a dispute” or “or has ultimate authority in a matter.” (Source)

As employed in P7 and P8 of the Trust Test, rinairs serves as the arbiter of any gray areas involved with any of TTG’s Allowable Changes.

The page on “arbitrary” explains why it is hard to come up with a less-strict standard than TTG that still results in trustworthy photos.