I posted last week wondering what would be different about a 3000 person con from a 2500 person one. As londo points out, really the question is what is different about a con with 300+ people on staff vs more like 250. And the answer (or at least an answer) turns out to be that 300+ people passes the size at which chains of trust encompass the whole committee. We will need new mechanisms for when a volunteer who appears to have authority for something violates that trust. We will need to establish and publicize an escalation mechanism. We will need to establish and publicize our expectations of our volunteers. We will need to establish a way of finding problems that we ourselves are causing before our attendees bring them to us, because we can no longer trust ourselves not to be the problem.
I'm so, so glad we had a chance to learn this gently, as Boskone and Minicon (which jumped straight to larger sizes) could not.