Yes, this was asked of me.
Once upon a time, I was in a clothing store paying for something. My boundary-trampling SIL (46 yo) says that her cousin is having surgery to reduce the size of her breasts. She stated she could not understand why? Finally, she said, oh so matter-of-factly, genuinely curious, "Does your back hurt because you have big boobs?"
I stood there stunned
Today I am more bold, but that day, I was not, and I just said "uh...no" and shook my head shocked at the incredible heights and depths of her rudeness, which knows no bounds.