Blair Warner: I don't go to wing-dings, I go to cotillions.
Jo Polniaczek: Well if that is a dance at the Hillcrest Country Club, then your cotillion and my wing-ding are the same thing.
Jo Polniaczek: There are people who in this world get shoved around and there are people who do the shoving.
Blair Warner: I just had another one of my brilliant ideas.
Blair Warner: Do you know what Jo's real name is? Joanna Marie.
Jo Polniaczek: Only my mother calls me Joanna Marie.
Blair Warner: Turn Blue.
Tootie Ramsey: There's going to be trouble.
Answer: The dramatic reason is to move the plot along. But in real life, store workers can be suspicious of groups of teens because of the perceived higher risk of Shoplifting. So the security guard may have seen them go into the changing room and decided to see what they were up to.