Just to answer a couple questions...
No, please don't just go around RPing the Unforgivables.... we are trying to keep some realism, and that will still get your character pwned if caught anyway. I would also call it an "uber ability" anyway. This would be one of those rules that is needed for day to day operation that we'll work on.
The "use common sense" thing there in the the "Cardinal Rule" should help to determine what is appropriate to RP and what is not. The intention isn't to be a free-for-all, just not nearly as (artificially) restricted as things have been. Do still expect IC consequences for IC actions. Without that, it's not really role play.
Just keep our heads about us, chaos isn't going to help either.
Until we really figure out specifics of what's going on, let's default to at least the basics of the way things have worked, just as a base instead of chaos. I.E. please RP humans, please RP your character is a student, don't metagame, familiars are still pets... order is needed, and those kinds of rules are likely to remain very very similar anyway.
Expect a new OOC book and a new Welcome Center in the next update. The new welcome center is going to replace the signs with an interactive NPC that explains the bare basics of the server to the new players, instead of hitting them with intense detail. The OOC book is an interactive conversaion that explains the full rules and guidelines of the server. But here's the best part... the book can be edited on the fly, without a server reset, and read out directly to the forums, both updating instantly upon a change. So we can work on this together.