For major failures, we plan a redundant system. For buoyancy, the redundant system is a dry suit. If your equipment is such that, in the event of a catastrophic wing failure (and they are rare) and USING your dry suit, you cannot swim to the surface, you are not diving a balanced rig, and something needs to be changed. You are not required to put the rig together so that you can swim it up with no air in the wing and no air in the dry suit, and all tanks full.