" Actions that excessively deprive others of the ability to experience various gameplay features."
http://nasomi.com/rules.phpThis is a stretch, I'll admit. But when one player suppresses supply on an item that doesn't have a ton of demand, but is a high priority item for the job that can use it, they're depriving (or at least creating an excessive barrier) to them experiencing that gameplay. However, I know for the most part Nasomi doesn't concern himself with that and I'm not asking him to enforce any kind of ruling on that.
In the mean time, I'll exercise my right to call out behavior I believe is detrimental to the server so discussion can happen.
Edit:
To Mr. Wiggin. I just want to point out, if people didn't sell to NPCs there wouldn't be gil to get from other players. There's not really that much gil generated by quests alone. So somebody has to be generating the gil directly from monsters for the economy to work at all.