Yeah, I see it like if you're holding up a pill bottle in the drug store, and someone walks up and asks if it works. Or, if you're buying a cleaning product and someone asks if it works for you. They're not implying that you're filthy, they just see you doing something they don't anything about, and they're curious, or just trying to say 'something' nice. If she was smiling, I really can't imagine that she intentionally said something rude!