Christina Unkel was 10 when she became a certified soccer referee. And in all that time, she said she can remember just one instance in which she changed a call after being confronted by a group of angry players.

She was 14, working a youth game in Southwest Florida, when she awarded a throw-in. As the team which lost possession protested vehemently, an opposing player stepped into the scrum and sheepishly confessed to touching the ball last.

“I’m like, ‘OK, well thanks for admitting that. I guess we’ll throw it the other way, right?’” said Unkel who, as an attorney in addition to being an official, knows the value of a confession.

Without that admission, she said, the protesting team’s pleas would have necessarily fallen on deaf ears.

“Could you imagine if someone comes up and yells at you, and you were very solid in your decision, and then you decide to change your mind?” Unkel said. “You’re not coming back.”

Referees know they don’t always get ‘em right, but imagine the chaos if they left every call up for debate. Yet that hasn’t stopped every soccer player who’s ever laced up a pair of cleats from arguing calls.

Soccer is the only major U.S. team sport in which that’s allowed.

Show up a baseball umpire, and you’re likely to watch the rest of the game on TV in the clubhouse. Say more than a few argumentative words to a football or basketball official and you’re likely to draw another foul. And don’t even think of talking to a hockey referee unless you have a “C” or “A” — for captain and alternate captain — sewn on your sweater.

But in soccer, anything other than the most obvious foul is often met with the aggrieved team surrounding the official in dramatic protest — sometimes even after the final whistle has sounded. Last Saturday, for example, after Indonesia lost a World Cup qualifier to Iraq by a goal, several players surrounded Chinese referee Ma Ning and his team. That didn’t change the result of the match, but Ning did hand three red cards, one of which went to a team official who shoved Ning.

That level of protest is the exception. But openly expressing frustration and displeasure with the officials is not.

“It’s part of the sport and it’s been that way for so long,” said defender Aaron Long, a World Cup veteran who wore the captain’s armband for LAFC more than a dozen times this year before his season was ended in July by a ruptured Achilles tendon. “So long as there’s a healthy respect both ways, the arguing and pleading your case, I think it’s all part of the game.”

Long said the fact the game stops every time a foul is called can also factor into the number of confrontations with the official.

“Soccer is so fluid,” he said. “And that fluidity gets broken up by their calls, right? So it’s like everyone is able to stop and argue in that moment.”

Inter Miami's Luis Suárez and Yannick Bright argue with referee Mario Escobar.

Inter Miami’s Luis Suárez, right, and Yannick Bright argue with referee Mario Escobar during a Leagues Cup quarterfinal match against Tigres UANL in August.

(Rich Storry / Getty Images)

LAFC teammate Timothy Tillman said since so many calls in soccer can go either way, there are few rulings that everyone will agree with. And if the percentages favor one side over another, that’s something worth discussing.

“There are many 50-50s,” he said. “If a call is always going against you, then you have to tell [the referee].”

In the game’s early days, there were no arguments with officials — largely because there were no officials. Disputes were resolved by the two team captains based on “gentlemanly” conduct. Later matches were overseen by two umpires, one provided by each team with an on-field referee — often the game’s timekeeper — breaking the tie in particularly sticky situations.

It wasn’t until 1891 that the laws of the game called for a single, neutral referee who was given full authority over play. (Incredibly, 134 years later, the game is still managed by just one on-field official despite the fact many of today’s players are world-class sprinters who are physical and have the vertical leap of a cougar.)

And shortly after that first referee blew his whistle to start his first match, the first argument erupted. That’s because, despite the game’s clear rules, many calls in soccer remain open to interpretation and timing.

“It’s because our sport flows and ebbs and there is a lot of gray,” said Unkel, a rules of the game analyst for CBS and host, alongside former World Cup player Lori Lindsey, of the Soccerish podcast. “You make some decisions that hey, maybe that would have been a simple foul in the 14th minute. But that’s never going to be a foul in the World Cup final.”

Long agrees that time and place matters.

“The way our sport is played, the fans can influence the referee in a lot of situations,” he said. “Home-field advantage isn’t just for the players. Sometimes when there’s like a little, tiny foul on a guy and you’re away and the crowd doesn’t do anything, maybe you don’t get it.

“But at home, the whole crowd all go[es] crazy, then he calls it really quick. So maybe that’s why we try to plead our case a little.”

Long prefers to stay out of those battles, believing his words will carry more weight if he speaks only rarely and stays on point.

“I’m not very feisty with refs. I don’t scream at them so that when I do talk to them, they’ll listen,” he said.

Evidence also helps.

“If there’s a little bit of blood on your sock or something, you could be like, ‘Hey, I got kicked,’” he said. “And they’ll be like, ‘Oh, I’m sorry I missed that.’ I don’t think they’ll change it in the moment, but they can register it in their head.”

Unkel, who became one of the youngest top-flight officials in the world when she received her FIFA badge at 25, agreed with that approach. She said two of the most effective captains she worked with were Becky Sauerbrunn and Christie Rampone, who played for the women’s national team.

“[Sauerbrunn] wouldn’t say anything. And then at times she’d come up to me, and in a very professional manner, she’d be like, ‘Hey, can you watch this? The attackers are stepping on [my] toes before the ball is in play’,” Unkel said. “So I was like ‘OK, I might be missing something.’

“But if you had the same player chirp and chirp, that player that’s just always on you, literally anything they say goes through one ear and out the other.”

There are certain lines players can’t cross, no matter the situation. Foul and abusive language, especially if directed at the official, can draw a quick yellow card; racism is a straight red.

Other than that, referees call ‘em as they see ‘em — even if half the people involved are convinced they saw it wrong.

“People are irrational when they play sports,” Unkel said. “One team is not going to be happy with you regardless of what decisions you make.”

You have read the latest installment of On Soccer with Kevin Baxter. The weekly column takes you behind the scenes and shines a spotlight on unique stories. Listen to Baxter on this week’s episode of the “Corner of the Galaxy” podcast.