Interesting story about the hand over the heart. In the US, only military personnel are supposed to salute at the forehead. Civilians are to salute the flag and the National Anthem with their hands over their hearts. As an Aussie, you may or may not have heard of the Pledge of Allegiance. It's a simple statement of loyalty that Americans learn in their childhood. It goes:
I pledge allegiance to the flag of the United States of America
And to the Republic for which it stands; one Nation, under God, indivisible
With liberty and justice for all.
Now it's original form was shorter:
I pledge allegiance to my flag and the republic for which it stands
One Nation indivisible, with liberty and justice for all
Before you started the pledge, you gave the military salute. When you spoke the words, "to my flag," you extended your right arm straight ahead and raised it at an angle towards the flag. Sound familiar? It was called the Bellamy Salute after Francis Bellamy, the Pledge's author, and it was very similar to the Roman Salute. In 1942, when the Roman Salute had become associated with the Nazis, the Bellamy was replaced with the hand over the heart. During the Second World War, the playing of the Star Spangled Banner at sporting events became commonplace and the new gesture was adopted for that as well.