How did Hazel react to Cassie's situation in Roll of Thunder, Hear My Cry?

This is the scene in chapter 5 when T. J., Stacey, and Cassie head off to the grocery store while Big Ma's visiting the offices of Mr. Jamison. Despite being first in line to be served, the storeowner, Mr. Barnett, conspicuously ignores the children and serves some white customers instead.
Tired of waiting around and being treated like a second-class citizen, Cassie starts getting angry and complains loudly to Mr. Barnett's face. As she does so, she hears a voice behind her telling her to shush. When Cassie turns round, she sees a woman called Hazel, who occupied the wagon next to her at the market. Mr. Barnett asks Hazel if Cassie belongs to her, but Hazel steps back from Cassie as if she has a contagious disease, meekly saying, "No, suh." Hazel's deference towards an angry white man stands in stark contrast to Cassie's more forthright, assertive behavior.