To appease her and play along with her, you could go on the service call and tell her that you tell her that this was not an uncommon problem and that you would be glad to adjust her service entrance panel to prevent those evil spirts from getting into the house through the power lines.
If she would like to pay for a trip charge you could inspect her service entrance panel, fiddle around some with the wires by straigtening them out, maybe remove a few from their respective breakers and magically reterminate them on the same breakers and say "that should do it." "You should have no more problems with those evil spirits coming through the electric lines now."
