A Costly Glass of Water

Joan and her boyfriend Fred, who lived in Stockport, were invited and given one of the ornate, if old-fashioned, bedroom suites for their stay. The party lasted the whole weekend and was a delightful affair. The catering was superb, and the congenial atmosphere turned the get-together of old friends into an unforgettable experience. On Monday morning, most guests had departed, and Joan and Fred prepared for their journey home. Having finished their packing, Joan looked around as if searching for something. She finally turned to Fred and asked, jokingly, "You haven't by any chance drunk the glass of water on the dressing table?" Fred nodded, and all of a sudden, pandemonium. Joan had to phone the automobile association's rescue service. Less than an hour later, an AA man arrived, hitched their car to his breakdown van, and towed the embarrassed couple home, where they arrived after a two and a half hour journey. Why?