Anatomical bilateral symmetry is a common trait  It follows, ttherefore, that it confers survival advantages on organisms
After all, if bilateral symmetry did not confer such advantages, it would not be common
If Powell lacked superior negotiating skills, she would not have been appointed arbitrator in this case. As everyone knows, she is the appointed arbitrator, so her negotiating skills are, detractors notwithstanding, bound to be superior.