THE China Motor Bus (CMB) company is investigating newspaper allegations that some drivers drank beer and then drove buses. The men concerned are still driving, pending the outcome of CMB's inquiries. The company has sent a warning notice to its stationsreminding drivers that drinking alcohol on its premises is banned. While drink-driving is illegal in most Western countries, laws do not exist in Hongkong. The CMB drivers, some of whom are said to be at the wheel for 15 hours, are breaking only company rules.