I took a power class that touched on the dangers in power substations. part of the discussion was on how to protect our equipment and part on protecting ourselves from stray and spurious ground currents. Fortunately for me I never had to go into a substation, but it was good information to know. We tend to assume that earth (ground) is safe as it sinks electrical currents. While that is true for the most part there are situations with high current and voltage where, as you say, there can be dangerous electrical potentials along the surface of the ground for several feet from the source. It ain't nothing to mess with. Always use your voltage detector! Take care of your electrical gloves and blankets and never touch the body of an aerial lift truck working around power.
I know, RKP5637, I am preaching to the choir.
Speaking of leaking underground power; I remember reading of a case where a dairy farmer went broke. He replaced cows but
milk production continued to decline. If I remember right it was solved too late for the farm. Buried transmission lines were leaking to the ground and then to the waterers. It wasn't enough to injure the cows but they didn't like it and were not drinking enough water. No water, no milk.
= new reply since forum marked as read