Here is the deal Glen,
A power line easement is an agreement between the landowner and the utility company for the power company to use and maintain. It is not owned by the power company. It's still owned by the landowner and they have the say who gets to trespass. You can be prosecuted by the owner. If it's not posted and you want to go by all means do as you do but you have no legal right to do so.
Defer to your attorney if you think I'm wrong. 😀