They wouldn't be for the batteries. With our Dual Battery set-up, both batteries are in holders with a strap holding them down. This could be true for the other side, since it is a small open space.
If we don't store or put anything on either side, guess we wouldn't need to have those on. Right? We store everything either in the cuddy cabin, under the bench seat or in the storage area in the gunwale inside the boat.