Tacho and the girls now have proof that Irma's conception of the US and of their journey is based on extremely outdated information. This means that Tacho and the girls must press on and figure out independently how the modern world works. In addition, the tone of this passage implies that being drunk on two beers is indicative of youth and immaturity, suggesting that Vampi and Yolo are young, innocent, and unprepared for this journey.