Not likely the boat would stay inverted long enough for that to happen. All that lead will be pulling the boat upright, assuming it was able to get upside down in the first place. Then too, the lead is encapsulated in the epoxy which would restrain any movement. The loose lead pigs in the bilge (outboard models) are another matter, but I don't believe there is enough room from the bottom of the bilge to the sole for them to reach escape velocity should the boat be inverted.