They announced there'd be no national anthem before the game. So the crowd did this!

The Fresno Bee (May 26, 2018): Before Clovis High played Buchanan Friday night for the Central Section softball championship, the announcer representing the section stated there wouldn't be a national anthem prior to the game.
Those in attendance at Fresno State's Margie Wright Diamond weren't having any of that. Following a loud chorus of boos, the patriotic crowd stood up and began singing "The Star-Spangled Banner" a cappella. Many removed their hats and placed their hands over their hearts. Others simply stood tall with pride.
Players stopped their pregame warmups to turn around and face the American flag that waved beyond the center-field wall.
When the song was over, the crowd burst into a round of applause.The teams went on to play ball.
Event coordinator Bob Kayajanian of the Central Section said it was a mistake on his part.