Waco, Texas

In the Big 12 Conference this college tennis season, schools are saying pish-posh to polite crowds and umpires who announce “Quiet, please!” at the slightest provocation. Tennis fans there have permission to scream, scream, scream—even during rallies and as players try to serve.

At Baylor last Friday, Nate Hilgenkamp, a 20-year-old...