My teachers were all wearing blue today, can someone tell me why?

Ok, so here is the information I have. So it was only about half of them in my school (I'm in highschool). The teachers that did it often hang out outside of school together, ex. going to a coffee shop. My assistant principal was also wearing blue, HE IS NOT IN THERE CROWD. They won't admit that it was anything but a coincidence . I think they knew that my assistant principal was going to wear blue (like he follows a schedule) and they were kind of making fun of him.

  What do you think?