After blowing a golden opportunity to break his opponent’s serve late in the second set of his match on Monday at the Miami Open, Jenson Brooksby, the rising American star, whacked his foot with his racket several times in frustration.

It was progress for Brooksby, who earlier in the tournament had escaped an automatic disqualification that many tennis veterans — and his opponent — thought was justified after he angrily hurled his racket to the court and it skittered into the feet of a ball person standing behind the baseline.

A week earlier, Nick Kyrgios, the temperamental Australian, narrowly missed hitting a ball boy in the face when he flung his racket to the ground following a three-set loss in the quarterfinals of the BNP Paribas Open in Indian Wells, Calif. The ATP punished Kyrgios with a $20,000 fine and another $5,000 for uttering an obscenity on the court, but he was allowed to play a few days later in Miami.

Kyrgios was at it again on Tuesday during his fourth-round match against Italy’s Jannik Sinner. He threw his racket to the court on his way to losing a first-set tiebreaker, prompting a warning and a point penalty for unsportsmanlike conduct as he shouted at the umpire, Carlos Bernardes. Then, during the changeover, he battered his racket four times against the ground, earning a game penalty.

“Do we have to wait until someone starts bleeding?” an exasperated Patrick McEnroe, the former pro and tennis commentator, said recently when asked about the flying rackets.

Racket-smashing tantrums have long been accepted as part of the game. Like hockey fights, they are a way for players to blow off steam. But as the broader culture becomes less tolerant of public displays of anger, and with an increasing number of close calls on the court, racket smashing suddenly no longer seems like an entertaining idiosyncrasy.

Mary Carillo, the former player and longtime commentator, said the tantrums have never been worse, especially on the ATP Tour, calling them “the most consistently uncomfortable thing to watch.” But chair umpires still resist meting out the most serious punishment.

“The reason for conspicuous leniency is that they have to somehow keep a match alive; there are no substitutions,” Carillo said of the chair umpires. “Tennis players, especially tennis stars, know they have incontestable leverage over the chair.

Like most people in tennis, McEnroe was stunned when the ATP recently handed down a suspended eight-week ban to Alexander Zverev, who repeatedly beat on the umpire’s chair at the end of a doubles match at the Mexican Open in February, coming within inches of cracking his racket into the official’s feet.

Psychologists have found that expressing anger physically tends to hurt performance and can encourage subsequent outbursts. In an oft-cited 1959 study by the psychologist R.H. Hornberger, participants listened to insults before being divided into two groups. One group pounded nails. The other sat quietly. The group that pounded nails was far more hostile to those who criticized them.

And yet these days, racket smashing feels contagious. There was Naomi Osaka’s display during her third-round loss to Leylah Fernandez at the U.S. Open last year. Novak Djokovic’s during the bronze medal match at the Tokyo Olympics. Even Roger Federer has had his moments. Rafael Nadal, by contrast, is famously gentle with his equipment and has said he never will smash his racket.

Even Andy Roddick, the former world No. 1, got cheeky on the subject, taking to Twitter last week with a tongue-in-cheek tutorial on how to safely smash a racket and whack a ball without endangering anyone.

Smashing and throwing a racket, not to mention swats of the ball — that hit, or nearly hit, and possibly injure people on the court or in the stadium — fall under equipment abuse in the sport’s rule books. To the frustration of some of the biggest names in tennis, those codes are more gray than black and white.

Martina Navratilova, the 18-time Grand Slam singles champion who is covering the Miami Open for Tennis Channel, expressed the sentiments of many after Brooksby’s racket made contact with the ball person.

“If it hit the ball boy, they need to disqualify him,” she said.

Brooksby and Kyrgios lost in Miami on Tuesday, but Zverev advanced to the quarterfinals and has a good chance of winning one of the top titles on the ATP Tour, even though some in tennis believe he should be on the sideline serving a suspension.

A spokesman for the ATP, which does not publicly discuss individual penalties, said Brooksby received a $15,000 fine, $5,000 less than the maximum $20,000 a player can receive for an incident from tournament officials. That amounted to less than half of the $30,130 he guaranteed himself by winning the match, not to mention the $94,575 he ultimately collected for making it to the fourth round.

Kyrgios was fined $20,000 for nearly hitting the ball boy after his loss to Nadal at Indian Wells, where he collected nearly $180,000 for making the quarterfinals. He, too, will earn $94,575 in Miami, less whatever fines he receives for his behavior on Tuesday.

Zverev, who has earned more than $30 million in career prize money, had to forfeit his earnings from the Mexican Open, and the ATP fined him $65,000, but the suspended ban has allowed him — in less than two tournaments — to more than triple in prize money what his outburst cost him.

The ATP is considering whether, given recent increases in prize money, an increase in fines could deter players. Fines for racket abuse on the ATP Tour begin at $500, compared with $2,500 on the WTA Tour.

Other than that, the codes for men and women are similar: No violently hitting or kicking or throwing a racket — or any piece of equipment, for that matter, and no physical abuse or attempted abuse against ball people, umpires, judges or spectators.

Still, tennis officials have a somewhat ambiguous understanding of when disqualification is warranted. It goes sort of like this: If you throw a racket or whack a ball at someone intentionally in an attempt to hit or intimidate them, you are automatically disqualified, whether you succeed or fail. But if you throw or smash a racket or whack a ball without consideration of its direction, and it ends up hitting someone, then tournament officials have to assess whether an injury has occurred.

If someone is indeed injured, as when Djokovic inadvertently hit a line judge in the throat at the 2020 U.S. Open, the player is automatically disqualified. But if no one is injured, as when Brooksby’s racket skittered into the ball person’s foot, the umpires will assess a penalty and tournament officials will fine the player — no disqualification necessary.

Brooksby and Zverev quickly posted apologies for their actions on social media and personally apologized to the people involved.

“I was grateful to have a second chance,” Brooksby told Tennis Channel on Monday.

Kyrgios is a repeat offender. In a news conference after the Indian Wells match, he berated journalists who questioned him about the racket toss that nearly clipped a ball boy’s head, and was unapologetic.

“It most definitely wasn’t like Zverev,” he said. “It was complete accident. I didn’t hit him.”

Only after an avalanche of criticism on social media did Kyrgios issue an apology. The next day, he posted a video of himself giving the boy a racket.

After his match on Tuesday, Kyrgios played the victim, criticizing Bernardes for speaking to the crowd while Kyrgios was trying to serve. He seemed not to understand why the ATP had come down so hard on him for the incident at Indian Wells, given, he said, that Denis Shapovalov had inadvertently hit a fan with a ball and received just a $5,000 fine. In fact, Shapovalov hit a chair umpire and was fined $7,000.

“I can throw a racket at Indian Wells,” Kyrgios said, “didn’t even hit anyone, and I’m getting 25 grand.”