Other mistake: When the car runs out of gas, the odometer is turning over from 22 to 23 miles. Since they were on the way back from a long trip out of town, the odometer reading wouldn't make sense even if the car had been purchased the day before the trip. Also, there is no way that a new car would run out of gas after 23 miles. They probably used a new car with a shiny new dashboard for the scene. (01:19:50)
Other mistake: A glass is dropped which had drink and one ice cube in it, however two ice cubes are picked up from the spillage.
Answer: As I recall, and it's been some time since I've watched the movie, Karen was part of the plot to have Margo miss a performance so that Eve, Margo's understudy, would have an opportunity to perform the part, for which she received rave reviews. Karen and the others arranged to take a day trip out of town before the performance, and then get "stranded" so they couldn't get back to New York in time for Margo to perform in the play.
raywest