The point at which a reader realizes that George Saunders’s third-person narrator might be speaking like (or using the voice of) the two main characters, Marie and Callie, might be early on when Saunders writes “etc. etc.” in the story’s first paragraph. The double “etc.” indicates quirkiness. It suggests a peculiar sort of character that most normative third-person narrators try to stay away from. In general (although there are exceptions), third-person narrators tend to stick to a formal, measured tone so as not to interfere with the personalities of the actual characters in the story.
The suspicion that the third-person narrator is more of a character is reinforced again by the end of the first paragraph. The “ha ha ha!” could also be described as quirky—a specific expression that points to an individual rather than a general narrator.
As the first section unfolds, the text regularly features additional moments that allude to a person. There’s the sentence fragment “But no.” There’s also the rhetorical question “Well, who could say?” Again, the conversational, informal style of the first section could make one realize that the narrator is not so different from the character.
It’s also possible that a reader will realize what’s happening at the start of the second section. The second part of the story begins with “Callie pulled back the blind.” The intimacy of this observation signals that the narrator is closer to the scene than perhaps previously anticipated. As with the first section, this section contains multiple moments that link to a distinct personality. For instance, the italicized “perfect” is a sign of a personal, individual idiom.