Daisy's subsequent death after spending an evening at the Colosseum with Mr. Giovanelli is a clear punishment for her spontaneous, emotionally driven behavior; permanent exclusion from European high society. Daisy's death is also considered a "common" death, because it's a death caused by a disease that people in high society have medication to cure. Daisy's punishment through death, and her death being considered a "common" death, is further evidence that spontaneous, risky behavior is correlated with the "common" class. Thus, as evidence through James' portrayal of Daisy Miller's character; European class boundaries are ultimately distinguished and maintained through individual behavior.
Throughout the course of James' Daisy Miller, we view European high society mainly through the judgment of Daisy by Mrs. Costello, and also to a lesser degree by Mrs. Walker. Even though these characters were born in America, they have lived in Europe most of their lives, and have adopted European culture and social customs as their own. Mrs. Costello's character is a more rigid adherence to "old money" values and behavior present in the European high society. While Mrs. Walker is a more reformed character than Mrs. Costello, she is similar to Daisy in that they are both very social beings. However, Mrs. Walker still embodies proper societal behavior and values, thus giving her credibility to the reader to accept her judgment of Daisy. .
From the beginning of Daisy Miller, James uses Mrs. Costello as the character that initially begins defining class boundaries through the behavior analysis of Daisy. Mrs. Costello initially warns Winterbourne against becoming involved with Daisy, as his association with her may taint his reputation; "I really think that you had better not meddle with little American girls that are uncultivated" (James, 21). This warning is preceded by Mrs.