The folks at WarCry have published a transcript of their recent IRC chat with members of the Warhammer Online: Age of Reckoning development team.
Q: Siege weapons have been recently introduced, but will they be available only in instanced RvR combat or will they also appear in the same or different form in real-world RvR?
Siege weapons are primarily slated for open world combat and Keep raids and not in Scenarios actually. The mechanics of them in open world vs. instanced Scenarios (if they're used in Scenarios) will be the same though. A catapult is a catapult...is a catapult. I think that's how it goes....