Resort to biting? It sounds like the dog is making a conscious choice. Dogs communicating and the humans refusing to listen? What's that? A Saturday Night Live skit? Are you saying that people are to blame when dogs bite?
A quick eye scan will tell you all you need to know, as dogs talk in postures, not words. If you strive to be a good dog Samaritan, listen with your eyes, and respect a dog -- no matter what their people might tell you.