Here is how I interpret section 301Unless otherwise stated, when the U.S. government speaks about being uniformed, it means its uniformed armed services. Therefore, when the U.S. Code refers being in uniform or not being in uniform, it only applies to members of the armed forces or veterans authorized to wear a uniform. It does not apply to persons authorized by state or local governments to wear uniforms or to persons authorized by private entities to wear uniforms. Thus, sections 301(b)(1)(A) and (B) only apply to members of the armed forces or veterans authorized to wear a uniform. Section 301(b)(1)(C) applies to everyone else, such as law enforcement officers, firefighters, etc., whether in or out of their uniforms. Section 301(b)(2) allies to everyone.
Law enforcement officers, firefighters, etc. in uniform who are also members of the armed forces or veterans should follow the procedures established by their respective departments. In the absence of such procedures, they should follow sections 301(b)(1)(A) and (B).
Dipping the Ensign
Merchant ships "salute" Navy ships by dipping their ensigns. When a merchant ship of any nation formally recognized by the U.S. salutes a ship of the U.S. Navy, it lowers its national colors to half-mast. The Navy ship, at its closest point of approach, lowers the ensign to half-mast for a few seconds, then closes it up, after which the merchant ship raises its own flag. If the salute is made when the ensign is not displayed, the Navy ship will hoist her colors, dip for the salute, close them up again, and then haul them down after a suitable interval. Naval vessels dip the ensign only to answer a salute; they never salute first.