As I'm sure you know, there is also the cultural aversion, almost a linguistic anomaly, to saying "I don't know" 我不知道 in China.

My knowledge of Chinese history and language is not adequate to fully understand this, but I recognize the practice and have developed coping mechanisms. When asking for directions or information in Chinese, if I notice a hesitation on the part of person, I will ask someone else (a face-giving distance away).

My students tell me they consider it 'impolite' to merely say "I don't know", even in English. They prefer to give random, albeit erroneous, information. A 'best guess', if you will. Or they will stay silent and study the floor. Saying I don't know is perhaps akin to leaving a blank space on an examination answer sheet, a lost opportunity and an admission of ignorance.