You can't make this stuff up.
On any other day at Live Oak High School in Morgan Hill, Daniel Galli and his four friends would not even be noticed for wearing T-shirts with the American flag. But Cinco de Mayo is not any typical day especially on a campus with a large Mexican American student population.
Galli says he and his friends were sitting at a table during brunch break when the vice principal asked two of the boys to remove American flag bandannas that they wearing on their heads and for the others to turn their American flag T-shirts inside out. When they refused, the boys were ordered to go to the principal's office.
So, showing patriotism is ok only on certain days? Why should an American flag T-shirt offend anyone celebrating Cinco de Mayo?
More at Hot Air.
Legal pondering at the Volokh Conspiracy.