Honking Twice
In the military, it is standard practice to honk twice in order to warn others that you are backing up. After going back to civilian life, soldiers still have the tendency to do this out of habit.
The Flag
Because the American flag is a symbol of the whole American nation, it deserves great respect. When they see the flag is being raised, soldiers will stand right away and even salute at times. No knee-droppers here.