There is no better example of the "all paths" parable than in neutral current. It really becomes complicated when you have wye distribution. The only answer is bonding, lots of bonding. Back in the olden days when the metal water system was a city wide bonding grid this was minimized but these days every house is it's own "earth". Ground ain't "ground" in any practical sense.
I measured the pole ground current on every pole on my street and got from less than an amp to over 8. My GEC is carrying about 3 with the main breaker off, about the same as the pole in front of my house. I may have the best ground electrode on the street tho (in ground pool). I do make sure I bond everything I can, every chance I get.
