What was the attraction of the West Gate at the end of the day?

At the end of the day, the attraction at the West Gate is that of an old woman exiting the city in a cart. When approached, the old woman claimed her cart was transporting her son, who was suffering from the plague. Needless to say, she was allowed to pass without close inspection. Unfortunately, there was no plague.... only the Comtesse and her family successfully escaping the city.