Our company which has tens of thousands of employees has about 60 users who have access to campaign in multiple instances. Being able to limit who of those 60 users can send out to large databases might help curb some of the email fatigue that people are feeling... because it would be more likely that instead of an email, those people would create a blog post on the intranet, or through another venue.

Org admins would be able to set a cap on users as to how big a database they can upload/attach their their mailings.