Quote Originally Posted by Ciaran
I´d consider it a feature, after all, while campaigning he´s usually not that easily accessible as he were if he sat in one of his palaces.
I lean toward it being a feature as well (as opposed to a bug), but I don't like to assume such things. It does make sense, though. Your faction leader is going to be harder to get a hold of if he's off campaigning for the summer, than if he's at home holding court.

And I don´t think it´s time coded; I´ve played often with the - notoriously rebellious - HRE, and sending the Emperor into a battle is definitely not recommended.

I kind of suspected as much, but it's good to hear that confirmed. Thanks Ciaran!