Why do soldiers wear 2 dog tags?
At this time, all military tags included a notch in one end. Historians say the notch was there due to the type of machine used to stamp the tags. By the 1970s, those machines were replaced, so the tags issued today are now smooth on both sides.
Civilians can legally wear dog tags. Yet, attempting to use the dog tags for personal gain may be considered an act of stolen valor, which is a punishable offense. Some veterans and active military members may consider it disrespectful, while others do not care.
Black Dog Tags are used by Special Operations forces such as the Army Rangers, Navy Seals, Green Berets, Commandos, and Delta Force. Black Dog Tags were mandated by a regulation on January 15, 1967 of the United States Army, Vietnam (USARV).
There's no specific protocol for what happens to dog tags after leaving the service, whether by discharge or death. Former service members do not have to return them to the military, but they also can choose whether or not to keep them.