There is a cultural difference that make the situation in Vietnam not so bad as it sounds. In Korea, as in Japan, the cultural norm is to refer to people by their family name. In Vietnamese culture, the given name is normally used.
As a native Korean, I'm sure that both A and B will notice the confusion and switch to full names at around the fifth or sixth line. Korean full names tend to be short so it isn't cumbersome, in fact full names are often used in the first place exactly for that reason.
The real problem by the way starts with multiple persons with the same or almost identically sounding names. My own name (Kang Seonghoon) for example is shared with at least 100s of other Korean people, including one famous singer who got arrested later ;-)
Good point about use of full names. Since you are a native, you might not have noticed this, but I find that as a foreigner operating in professional settings, I only hear people referred to in English as $title+$family_name. Aside from my office mate, I can't think of the given name of anyone on campus.
Speaking of having identical names, the one that cracks me up is 김정은.
Wasn’t this caused because when the country adopted surnames, people were allowed to choose their name, and most people chose the name of the current ruling family?
The explanation I saw was tax farming. You don't have a surname, so for the Emperor's purposes, you're getting the surname of the guy who collects your taxes for me
> By some estimates 30 to 39 percent of Vietnamese people bear this surname.