We don't have many special rules here. Most of the infractions listed are common to all forums. We have the "no public discussion of moderator action" rule because this is what works better for us based on our experience running this forum. We used to allow public discussions a few years ago but it didn't work well and in most cases it not only failed to resolve problems, but made problem worse.
Warnings for PDMA only account for a very small percentage of moderator actions, partly because it's been in place for some time and most people know the rule.
While some moderator actions can be handled in private, public moderator actions can not be avoided because the audience is often not limited just a single user, but other users participating in the discussion too. The new infraction system we are testing actually allows more moderator actions to be done privately, because it makes it easier to send notice.