If the "Audit" setting for packages had three settings instead, would that solve your use case?

Audit: Off
Audit: Commits not authored or reviewed by a package owner
Audit: All Commits

Yes, that would also solve the problem for me, and would probably be an easier option for new users.

I suggested the Herald solution, as it might be more flexible for other's needs, and the decision to change the Owners behaviour seems to have been deliberate, so I wasn't expecting much motivation for changing it there. But ultimately it is your decision how/if/when to fix it.

On second thoughts, the flexibility of a Herald rule may already be better for me, as I want to filter out Merge Commits from auditing (at least when they are merged by an Owner), since the individual commits that are merged already have their own audit.

Again though, this may be a universal thing that most users will want so it may be better handled by always filtering those out, though I imagine there are some users working in an environment that is so tied down in process that they need to show that they are auditing every single change, even when the change is just a merge of other already audited changes.

We're looking for a similar concept for Reviewers:
Even if the Author of a review is one of the Owners, we still want to automatically add that package.
This is mostly just T1125 - we want to make it easier to assign reviewers, and Owners has good UI for selecting paths.

Using Herald for this just ends up with extra work (Write another rule for each package).