The New York Knicks and Philadelphia 76ers each blocked a fan and apologized for actions against opponents during the qualifiers on Wednesday.
The Knicks allegedly banned a man by spitting at Atlanta Hawks Trae Young during Game 2 at Madison Square Garden.
"We investigated the matter and found that the owner, who is not the owner of the season tickets, spat on Trae Young, and for this reason, has been permanently banned from The Garden," Knicks said in a statement. "We apologize to Trae and to the entire Atlanta Hawks organization for this fan's behavior."
Atlanta Hawks takes care of Trae Young (11) controlling the ball against the New York Knicks in the second half of the Eastern Conference quarterfinal match at Madison Square Garden on May 26, 20201 in New York.
The Atlanta Hawks watched Trae Young (11) control the ball against the New York Knicks in the second half of the Eastern Conference quarterfinal match at Madison Square Garden on May 26, 20201 in New York.
The behavior was "absolutely unacceptable and will not be tolerated in our area," Knicks said, adding that he would not pass any information on to authorities.
New York City police said the complaint had not been lodged until Thursday afternoon.
The 76ers said a fan who threw popcorn at the Washington Wizards guarding Russell Westbrook as he walked out of court in the fourth quarter after an injury at the Wells Fargo Center would have his tickets canceled for the season. He was also banned from all activities on the court.
The 76ers called the behavior "unacceptable and disrespectful" and said it had no place in sports or the stadium.
No group has released the names of the fans involved.
NBA stadiums have recently begun to allow fans to return in full or near.
Westbrook told reporters after the game that the behavior of some fans was getting worse.
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"This s --- is out of hand, especially for me," he said. "The amount of disrespect, the number of just fans who do whatever f --- want to do. It just comes out of the pocket man."
Westbrook said in any other case, such incidents would not happen. A man would come to her on the street and pour popcorn on her head, she said, because "she knows what's going to happen."
Young's father, Rayford, said things needed to be done.
He wrote on Twitter on Thursday morning saying: "@ russwest44 throws popcorn at him & @TheTraeYoung gets spit on. I can handle all the songs about my son, it comes with it. But this needs fixing."
Los Angeles Lakers player Lebron James has called on the NBA to protect its players.
"The way we AS PLAYERS want to see who throws that popcorn on Russell while leaving the game tonight injured !!" James wrote on Twitter. "There are cameras all over the stadium so there's no reason!"
The NBA said on Thursday that it would "significantly improve fan behavior" going forward.
"The return of many NBA fans to our stadiums has brought a lot of excitement and energy to the start of the finals, but it is important that we all show respect for our players, officials and our fans," the league said.