My mom teaches kindergarten, has for nearly 26 years. The week before classes were going to start a few years back (while she was doubling as principal), she noticed that the headmaster and she had accidentally placed the 2 4-yr-old classes in almost complete segregation. As soon as she saw it, they fixed it, no one ever had to find out. It really saved their butts from the unintentional appearance of racism that time.