This is the heart of the issue. You can't write an (unintentionally) ambiguous policy to manage grey areas.
We have to trust the moderators. If there's a general problem with moderation then a backlash will ensue from the board members and it will become obvious. But as far as I can tell the moderation here is good and I, for one, am happy. This is one of the most peaceful and harmonious forums I've been involved with