During Luke and Manny's play, the lyrics claim that China "gave us Jackie Chan." Jackie Chan was born in Hong Kong, a separate entity with its own legislature, not China.
A series of cars drive by Claire and Haley in the van and honk/wave after seeing the suggestive ads on the sides of the van. If one assumes the cars honk once they see the ads on the side (not the back where Phil, Luke and Alex are shown) the last car that drives by honks much too early, i.e., at a point where they would not be able to see the side yet.