Diablo III is for real

[Quark]

If I join a game to play PVE and progress my char, some ahole doesn't pop in and PVP my party

The early outlook on this is promising:

I won't deny there are some that would enjoy nothing more than to see others frustrated, but is that truly something that should be encouraged through design - if not directly opposed?

We have a large focus on cooperative play for Diablo III, and the mechanics and design decisions related to multiplayer are likely going to be based on supporting and encouraging it as much as possible, and not breaking it down.