Fan experience in Japan essentially means interactivity. Or at least, perceived interactivity. Japanese fans cheer in unison, chanting "unique" songs for every player (really, many of them have the same melody, and just include the player's name and a couple other words).
Fans in Japan - anime, idol girl music groups, and baseball - often feel like they are a part of the production. The word "supporter" often comes up when I talk to my students. They "support" their favorite anime (or anime character) by buying merchandise. They "support" their favorite girl by buying her souvenirs, or buying lots of CDs to give her more votes. And they "support" their baseball team by singing and clapping.
One song you'll always hear is sung when their team comes to bat in the seventh inning. Similar to the seventh inning stretch in the US, at the top of the seventh, the visiting team's fans sing their team's fight song, and in the middle of the seventh, the home team sings along.
For many teams, the song's climax is celebrated by releasing long phallic balloons into the air, resulting in a loud screeching sound as they deflate and flutter around the stands.
But thanks to fears surrounding the coronavirus, the balloon release has been banned by the Tigers and the BayStars. There are teams that don't use balloons at all anyway - the Swallows fans wave little umbrellas in the air. And I'm sure other teams, like the Hawks, Buffaloes, and Golden Eagles, will also ban the balloons in the near future if they haven't already.
And while this ban seems to be only during the teams' spring training games, I could see it continuing on for a while into the season. And while it's a spectacle to see in person, it's quite wasteful - something like 20 million balloons (assuming 40,000 balloons at 500 games) per year. (It probably brings in some big cash for the teams, though - the balloons tend to run about $1 each.)