My son was about 5 when we went to a fast food restaurant and on our entering there, we saw two policemen carrying pizzas. My son asked loudly: "Mom, why aren't these COPS having doughnuts?"
Also it's not very common in our country to see women wearing hijabs so my 4-year-old son sees a group of muslim women at a seaside resort and he asks (this time not as loudly): "Mom, are they NINJAS"
Children are very open and they speak their minds which could sometimes embarrass adults