In what way do the rules around formal introductions represent the superficiality of traditional English etiquette in the novel, The Victory Garden?

The author makes special note of the way Emily was brought up to understand and follow the strict procedure that prohibits you from interacting with someone until you are properly introduced and when Robbie learns of this, his amusement and incredulity highlights how trivial this convention really is. Thus, the author uses the rules around formal introductions to represent the superficiality of traditional English etiquette.