So, a rule that says that any time a reliever enters a game with men on base and immediately issues an intentional walk, that runner belongs to the previous pitcher? I gotta think there'd be some unintended consequences there, but also, it seems unlikely to ever happen now that you don't have to throw a pitch.
I don't imagine having Arrieta issue an "old-school" walk would have worked because why even stress his arm, or risk a wild pitch?