Travelling at height is a safety breach, end of the story. The company policies and procedures and training manual should state this clearly. If a person is breaking those rules in relation to safety, they should be instantly dismissed. Nobody, you, me the boss or owner of the company or that eejit clown, fool dope has no right, whatsoever to put everyone else in danger. Go through the proper channels and show others that the company is serious in relation to the safety of the employees.