4mastacker
You ask a very good question. In very simple terms, the answer is electrical bonding.
Too many regard this as a design issue - once designed and implemented, that's it. Forget it. But many factors can adversely affect bonding, and hence the safety of the aircraft. A typical example. Corroded joints in which ground currents are flowing can transmit RF radiation. And when faced with the likes of intergranular corrosion,the reduction in strength due to the corrosion is disproportionate to the reduction in thickness of the metal. It follows that, if you penny pinch and skimp on maintenance, the risk increases. (Just illustrating linkages).
Too much wiggly techy stuff. My brain hurts already. Suffice to say, it is critical to the safety of the aircraft. But to my knowledge there is no suggestion this is relevant to XV230.