Uniform Shop Macomb Mall Is It Against The Law For A Police Officer To Buy Things From A Shop While In Uniform?

Is it against the law for a police officer to buy things from a shop while in uniform? - uniform shop macomb mall

I remember reading an article in which a seller refused to serve a police officer, because it in uniform, and said that he had used to break the law.
Several times I saw the police uniforms, buy things in supermarkets, so they violate the law or what has changed?