This tradition began as a Naval tradition and is similar to the tradition of the hand salute in that the purpose is to show a lack of hostile intent by showing that you were unarmed. The naval salute was done by approaching or vanquished ships as a show that they had no ammunition on hand. The original process was for the approaching ship to shoot up all of its ammo so that it didn't have any left to shoot at you. The hand salute is done for the same purpose. The right hand is used in the hand salute to demonstrate the lack of a weapon, thereby showing a lack of ill will.

In 1842 the United States declared the 21 gun salute to be its Presidential salute. The 21 gun salute is fired upon the arrival and departure of the President. It is also rendered for former presidents, the president elect, foriegn heads of state, and members of royal families.

The wearing of a military commemorative ring is another time honored tradition but is not limited to presidents, and heads of state. Anyone who has a story to tell can use a military ring to do so. 

The irony of the story is that when you salute you display your ring with all of your accomplishments.