✔ 最佳答案
You are absolutely correct. 台灣護照就是我們在國外的身分證 I am surprised that BA did not even trained him to recognise passenger's passport.
Actually, a lot of countries in the world does not even have ID card (e.g. USA, UK, Japan) Passport is the only recognised type of document to identify yourself outside your country, so ID card has a LOWER authority of identity purposes. (Some country don't have centralises ID database. In USA, only the individual states issue driving licence and ID card) Only national government can issue passports. So the authority is HIGHER.
Hong Kong is a special case that you do not need to use passport to depart, because some people are flying to Mainland China and they do not need passport to fly. On top, many HK residents are not even using HK passport to go to another country. They use their Australian, Canadian, American....... passport to fly.
It is possible to use HK passport to leave HK, but it is a little more inconvenient for the immigration officer, and many people don't even notice that.
With regard to that nosy BA staff, you could have told him/her to shut up, because his main job is to check whether you have a valid passport and visas for your destinations and check-in your luggages. That's all! I do not see why (s)he is asking you all these questions, 你的生日?你有幾個兄姐? It is entirely out of his scope of work. Exactly, who is he calling to check whether you have just one piece of check-in luggage? I think you became another victim of bored check-in staff wanting some laughs.