On the subject of bias, or maybe the appearance of bias, it might be wise to require that a moderator who ''moderates" a post or thread post the rule or rules broken where the "moderation" takes place. A simple cut and paste of "violation of rule x, blah blah woof woof".
It is a requirement on a couple of boards on which I volunteer as a moderator and tech guru.
We had some problems on one of the boards, and it reached the point where there were complaints about moderator bias. It seemed to make a difference, it cut down on the bias claims and such.
The only person the moderators on those boards answer to is the owner. However, there is sort of a "peer review" process
that is available, and the moderators try to discuss things
pertaining to the task at ahand and what goes on, in an attempt
to prevent both members AND moderators from drifting, intentional or not.