Martha, a homeowner, decorator and magazine publisher, contracted with Bob, a self-employed carpenter, for the performance of certain carpentry repairs to Martha's two-story home which was expected to take only a couple of hours of Bob's time. 

At some point, Bob leaned a ladder against the house so he could climb up to remove a tree branch that had fallen on the roof during a recent storm and was blocking his access to the repair site. Because the ground was uneven, Bob asked Martha if she would stand next to the ladder and brace it to keep it from leaning. Martha politely agreed and braced the ladder as Bob made it safely onto the roof.

Thinking that Bob did not need her to brace the ladder any longer, Martha stepped away from the ladder and walked away. As she was returning, Martha looked up just in time to see Bob sliding off the roof as the ladder had suddenly leaned under the pressure of his foot on the top rung. Bob fell to the ground below where he suffered immediate and severe injuries, primarily to his face.

Immediately following the incident, Martha called 911 for an ambulance, then called Bob's wife, Viola, to meet Bob at the hospital. By the time Viola arrived at the hospital, the doctors had already begun emergency surgery to reconstruct Bob's severely injured face. Viola anxiously waited to see Bob in the recovery room.

When Bob was rolled into the recovery room, it was clear to Viola at first glance that Bob's injuries were quite severe and that his face would never look the same. Viola fainted briefly, then regained consciousness, wailing in distress that their lives together would never be the same. Only after months of therapy did Viola begin to reasonably cope with what had happened to Bob and the effect it would have on their marriage, but she could not let go of her anger and wanted Martha to pay for it.

What defense(s), if any, should Martha raise to a claim filed by Bob under the Louisiana Worker's Compensation Act? Is Martha likely to succeed? Explain.