I think Meta-Moderation is a nice idea, and should be considered wherever there are moderators wielding power, even if it is over fairly innocuous domains such as message posting.
Personally I agree with the vast majority of decisions, over 95%, which is probably not a surprise to anyone who has done a lot of Meta-Moderation. But I wonder about some immature kid who gets his kicks marking things "Unfair" (or whatever the appropriate term is for that message). Which gives rise to the concept of Meta-Meta-Moderation, where the Moderators rate the Meta-Moderators.
The idea is that every Meta-Moderator would be ranked by the percentage of the time they disagreed with the Moderator. If a Meta-Moderator disagrees with a huge fraction of moderator choices, they are probably not that serious about their duties. Isn't it reasonable to expect that most moderations are fair?
Meta-Moderators with a high percentage of "disagreeable" responses would have their Meta-Moderations derated, i.e., not count as much as those who tend to agree with the Moderators' opinion. That way, the one time in 50 I say a rating is "Unfair", it would carry more weight than the vote cast by a kid who always says every rating is unfair.
This seems to be a way to filter out the noise and make Meta-Moderation more accurate, in my view.