In the case of the supreme court held that police departments are allowed to regulate officer appearance.

In the case of Keller v. Moseley , the supreme court held that police departments are allowed to regulate officer appearance.
One major factor that influence the judge decision is the undercover situation that the police have to constantly do. In order to find information about a specific gank for example, they need to go and disguise themselves either as a client or as potential recruit for the game