Now. What if you don't know they name, just have a picture of them. (Imagine that you are a guard, and you need to find out who is the terrorist, do you really want to call they name out loud?)
So now, replace person by pig. So that they can't cause any harm, and can't answer any of your questions, can't say anything. And those pig are trained to stay in line. You are in the head of the line. You can let only one pass your gate as a time. And you need to filter out only one pig. The way to recognize it is by looking for its name, which is written under the pigs' neck. So, obviously, you can't see the name as a long distance also. What would you do?
Let's imagine:
What is a fastest way to search?
Any idea to find/looking for something faster?