In my years of engineering for a power and gas utility company, I have identified hundreds of stray voltage cases but corrected only a few. When present, they are mostly unavoidable or massively hard to correct. This is a classic Murpy's law area. There are untold sources of ac and dc and mixed acdc leakage, many of which are dangerous or at least annoying. Loss of utility neutral is one of the most dangerous, both on the distribution system or even on a service to a building. There are tens of thousands of miles of utility primary cables with concentric neutrals out there that were installed direct bury and the neutrals have corroded to failure. This is particulary the case in soil containing nitrates and phosphates, such as former farm land. Former farm land is a synonym for housing developments with buried utilities, as you know. And people wonder why they get shocks in swimming pools. You can commonly measure a voltage gradient across the surface of a pool and another gradient in the same spot just from a difference in depth. If you install ground rods at extremities of a house property you can read some amazing voltages and stray currents. I have meausured 15 volts between the neutrals of adjacent houses. It goes on and on.