Which side are you on?

Reader's　Digest 4月号の記事 "Life in these United States" からの引用です。

It was my wedding day, and no one was happier than my 78-year-old mother. But as she approached the church doors, an usher asked, "Which side are you on?"
"Oh, no," she said. "Are they fighting already?"

ずいぶん早とちりの母ですね。