At work, among others, we have overhead power lines for the main grid connection (400 kV, about 1600 MW). The power lines cross a parking lot, and the positions directly under the power lines are blocked with large rocks.
There are some ideas about the reason why parking is not allowed under the power lines, including protection from exposure to electric and magnetic fields, protection from falling ice (it’s in a Nordic country), protection from downed power lines, protection of the power lines (which need a very high availability) from accidents (i.e. fire) of parked cars, and accessibility of power lines for maintenance (however, moving any cars would be easier than removing the rocks).
Anyway, what is the real reason why parking is not allowed under the power lines?