I am aware of two cases of "stray voltages". I was present when a child was shocked when exiting a pool (NOT electrocuted) which was not properly bonded. The cause was a power line contacting the neutral of the single phase supplying the home. In the other case, we investigated leaking copper pipes joints in a home where a 110 kV line had fallen onto the ground right at the distribution transformer supplying the home was grounded. The resulting current was sufficient do damage the plumbing.