It is illegal to attach a vending machine to a utility pole without prior consent from the utility company.

RCW 70.54.090
Attachment of objects to utility poles.

It shall be unlawful to attach to utility poles any of the following: Advertising signs, posters, vending machines, or any similar object which presents a hazard to, or endangers the lives of, electrical workers. Any attachment to utility poles shall only be made with the permission of the utility involved, and shall be placed not less than twelve feet above the surface of the ground.