Grounding on Cable and Telephone lines Issues.
Grounding and interactions with powerlines is a very complexed issue at times. Multi grounded system neutrals are attached in hundreds of places and interface to stabilize the electrical systems. All sources of energy are trying to go back home to earth. The terrain and earth is a variable and if your location is the best path guess what it attracts attention. If there are induction hazards or stray voltages of metal isolated and in a magnetic field they all are sources. Harmonics are in play as well. Loose hardware or spacing issues are just a few of the issues. Ground connections and corrosion become partners in all this. Using your voltage detection equipment with many times register in hundreds of volts. It all says that applying pole grounds can increase or decrease the hazard but with out doing lots of detective work it cannot be specifically answered. In the last twenty years homeless people also steal pole grounds for money. Poor people.
I know this is not a clear answer but I hope helpful.