In Hong Kong, one of the world’s most expensive cities, 79 yuan (US$11) will get you a set lunch for one. But, to the surprise of many, it will buy a day tour for two people, with lunch and a visit to several attractions thrown in. With such budget tours becoming increasingly popular among mainland Chinese visitors, especially those from the nearby cities of Shenzhen, Zhuhai and Guangzhou, the Post joined one on a weekday to see how they operated. At 8.30am, a coach packed with about 60...