recently in my game we lost with wildlings with card The Horde Descends.
Baratheon was considered lowest bider and he had to:
"Baratheon has to destroy 2 units at one of his Castles or Strongholds instead of 1 unit anywhere."
and he destroyed ships in Blackwater Bay.
Should it be allowed? He can muster ships there, so it counts as a castle area? I will add that he had land units available.