First, I know you moderators take a lot of grief for being inconsistent with deleting posts and punishing offending members, and I can appreciate that it's a difficult job.
Having said that, there's no public accountability or awareness to who gets punished and how often. The current system is that a suspect post is made, it is flagged for moderator advisement. Many times, the post is deleted, and as far as every other user is concerned, that's all we know that results from the matter. If there is a suspension doled out, only the suspended person is made aware. The old A.net community board would at least display on a user's profile whether or not that person is currently suspended, so we had an idea that if somebody really fragrantly violated the rules, they were being properly punished. When we don't know who really being punished for serious rules violations, it leads to the gripes against the moderators for inconsistency
I don't know what the most proper way to inform the community about those who are being suspended for rules violations is, but I think the lack of transparency in the matter is what leads to all sorts of suspicions about people having multiple user names, going away for awhile and coming back with a fury. Maybe you can build a link to the list of suspended members through the site related forum, so that way those who care are able to reference the list. And for a certain level of privacy, you could set it up so that the list can only be accessed by members who are logged in. In the past, I've twice received 3 day suspensions for forum rules violations, but is that the only level? Are there week suspensions? Month suspensions? What leads to permanent expulsion?
Additionally, though I can understand why you moderators wouldn't go for it, the punished list should include which moderator issued the punishment.
"All human activities are doomed to failure." - Jean Paul Sartre