I think most of bodyguards wearing sunglasses are just for the looks. However, they could see clearly and protect the eyes from the uv rays in the strong sun lights. They will not only look cool but also see clearly through the sunglasses. The sunglasses now are the fashionable things which will make us look different.
It is not just only to be cool. Studies show that wearing dark sunglasses can intimidate other people. Usually, a boyguard is a type of security operative or government agent. They protect a person, usually the person is famous, wealthy or an important political figure. And a lots of bodyguards wear dark sunglasses and clothes to follow the person to show the conspicuous.
With the development of modern society, people are more and more aware of protecting privacy. We can easily see people, especially famous people love wearing sunglasses. Some think they can enhance outlook by wearing sunglasses. While others wear sunglasses want to look cool or even pretentious. Actually, the truth for bodyguards to wear sunglasses is that they consider means of privacy protection. And also keep mysterious. Sunglasses, specially the mirrored brands, aid a high profile prevent eye-to-eye contact when he desires or has to live living of a typical private citizen.