A Question About The Movie "Anastasia" (1956)

I always wondered about a scene in the movie. When General Bounine (played by Yul Brynner) is taking Anastasia to see her grandmother in Copenhagen, the cab driver halts to allow the King’s Guardsmen (on their daily changing of the guard parade) to pass. General Bounine crosses his index fingers on both hands…he explains that he was a cavalry general, and the cavalry always did this when the infantry marched by.
I never heard of this custom-anyway, why was it included in the scene?

I don’t know the answer to your question. I just wanted to chime in and say I lovelovelove this movie. The music is wonderful. I saw Yul Brynner in person in The King and I a couple of years before he died. I was in the eighth row. Commanding presence.