Everybody knows the cummerbund is to be worn with the pleats up (to catch crumbs). Originally, men used to put concert or theater tickets in the pleats.
Okay, not everyone. The US Army manual says the pleats go down. Dane's dad spent time in the army and Dane learned from him. If you ever see someone wearing their tux with the pleats down, they learned from someone in the army.
I've always worn them pleats down and have that story to tell.
My readers pay attention to the details and I love that.