A loud portion of the fans who were able to attend the first game of the NFL season Thursday night didn’t appreciate the social justice demonstrations before kickoff.

All but one member of the Kansas City Chiefs stood during the national anthem, but the Houston Texans remained in the locker room while the song played at Arrowhead Stadium. Houston players and coaches also weren’t present on the field as Alicia Keys sang “Lift Ev’ry Voice and Sing.”

After the two songs played, the Texans and Chiefs locked arms in the middle of the field for a moment of unity. Boos could be heard from the crowd as the players stood in silence, confusing members of both teams and viewers at home.

“I thought that that was a nice thing to do, so I’m not sure why they would boo that,” Texans coach Bill O'Brien said after a 34-20 Chiefs’ win. “Maybe they were just booing us 'cause we had just come on the field as the visiting team. But yeah, I thought that that was a nice gesture.”

This wasn’t the first instance of fans booing players this year because of demonstrations against racial and social injustice, even though most sports have been played in empty venues. A portion of the nearly 3,000 spectators at an MLS game at Toyota Stadium booed after players from FC Dallas and Nashville SC knelt during the national anthem last month.

“The moment of unity I personally thought was good. The booing was unfortunate in that moment,” Texans defensive end J.J. Watt said. “I don't fully understand that. There was no flag involved, there was nothing involved with that besides two teams coming together to show unity.”

Kansas City’s announced attendance for the opener was 15,895. The Jacksonville Jaguars are the only other team that will host fans with limited capacity in Week 1.

If fans were upset that the Texans weren’t on the field during the national anthem, it might not be long before players get booed before kickoff again. Players from the Miami Dolphins said in a video Thursday night that they will remain in the locker room for the national anthem Sunday, calling for action instead of “empty gestures” against racial inequality and police brutality.

The Dolphins will visit the New England Patriots in an empty Gillette Stadium in Week 1. Miami can host up to 13,000 fans when it plays the Buffalo Bills at home in Week 2.

Expect more protests and demonstrations Sunday and Monday when the rest of the league opens their season.

A Washington Post poll indicates that most Americans believe it is appropriate for athletes to kneel during the national anthem to protest racial inequality.

Kansas City Chiefs and Houston Texans players line up for a moment of unity ahead of their season-opening NFL game
Kansas City Chiefs and Houston Texans players line up for a moment of unity ahead of their season-opening NFL game GETTY IMAGES NORTH AMERICA / JAMIE SQUIRE