Actually, I feel no defense is needed for the designer. The only time you see a plug for Above The FlaT (the official business name) is on pro bono work. And even then, a conservative link is tucked away so as to not take away from the deisgn. Clients, searchers, the business. Those are the priorities.
Besides, such a tactic would be counter productive for the designer. As a consumer, if I saw a site I liked, I would find my way to the designer well enough. If I was a design I like, but with a self promotional tag too prominently placed on the site, I would suspect my site would receive the same treatment, and I would continue my search.