The incident with Kevin Smith was nine years ago. And was essentially a misunderstanding related to the Customer Of Size policy, which has since been revised to make it easier to access and reps given direction regarding sensitivity when enforcing the policy.
I'm a larger person, but not quite a COS, and have never really understood the anger at Southwest, who gives a COS an extra seat on the plane for free. I assume some people are very sensitive about their weight and adverse to any extra attention drawn to them, which is understandable. And the occasional Southwest rep may not handle the situation with the necessary tact. But if someone qualifies I suspect they are aware of their size, and if they take the necessary steps to be given a free seat ahead of time there should be no need for any embarasment.
