Users should be able to set who can see or edit (or at least just who can edit) Herald rules.
Specifically for cases where Phabricator hosts the git repository, I want to ensure that under no circumstances is a commit to be landed if persons A, B or C have not signed off on its differential review. I can set a Herald rule to decline commits of reviews that haven't been accepted, and I can make it so those people are blocking reviewers of changes to a block of code, but all of those rules are global and can be edited by anyone.