A municipality local to me (New Lebanon, Ohio) "just did it" and hung 150 banners honoring local veterans from power poles. The local monopoly power company threatened the municipality with >$300 per-pole hanging fees and demanded they be removed. There was some back and forth but eventually the power company gave-in to public sentiment (honoring veterans and all). I would suspect "just doing it" would put you on the business-end of civil, if not criminal, litigation.