The PGA Tour has been urged to do more to protect integrity.

US.- Concerns have been raised about the influence of sports betting in golf after an incident in which two fans were ejected from the BMW Championship for shouting at Max Homa on the 17th green. The incident in the third round of the second FedEx Cup play-off event was reported to be related to a three-dollar bet between friends.

Homa said afterwards: “I love that people can gamble on golf, but that is one thing I’m worried about. It’s just always something that’s on your mind. It’s on us to stay focused or whatever, but it’s just annoying when it happens.”

Masters champion Jon Rahm has echoed the concerns, warning that the PGA Tour will find it “extremely difficult” to prevent fans who have gambled from trying to affect the outcome. Speaking ahead of the Tour Championship in Atlanta, Rahm said comments like those that led to the ejections were more common than many people realised.

“I feel like we hear it every single round. That happens way more often than you guys may hear. I mean, it’s very, very present. In golf, spectators are very close, and even if they’re not directly talking to you, they’re close enough to where if they say to their buddy, I bet you 10 bucks he’s going to miss it, you hear it.

“Luckily golf fans are pretty good for the most part and you’re hearing the positive, I got 20 bucks you make birdie here, things like that. But no, it’s more often than you think. I think the tour maybe should look into it because you don’t want it to get out of hand, right?

“It’s very easy, very, very easy in golf if you want to affect somebody. You’re so close, you can yell at the wrong time, and it’s very easy for that to happen. So I think they could look into it, but at the same time, it would be extremely difficult for the tour to somehow control the 50,000 people scattered around the golf course, right?

“So it’s a complicated subject. You don’t want it to get out of control, but you also want to have the fans to have the experience they want to have.”

PGA Tour commissioner Jay Monahan told ESPN.com that the recent incident was “unfortunate”.

“Our fans have great appreciation for the integrity of the competition,” he said. “They’re respectful of our players. We have seen that continue to be the case and expect that to continue to be the case. We have tremendous fans that have tremendous respect for what these players need to do in order to provide and present the tremendous performances they do.”

The expansion of sports betting in the US has provided an opportunity for the PGA Tour, whose marketing partners now includes bet365, BetMGM, BetParx and DraftKings. That contrasts with the R&A’s stance in the UK. It has resisted betting deals because of a concern for the image of the sport.

The Guardian’s golf correspondent Ewan Murray wrote after the incident: “Golf has had a strange relationship with gambling for some time. A bit like watching Naked Attraction, so many within the sport do it without ever admitting as much. As the beast grows in the US, integrity of competition must be fiercely protected.”

He warned that at lower levels there is “obvious scope for golfers to become embroiled in nefarious activity”. He noted that unlike in tennis and snooker, there has never been evidence of tampering with outcomes, but voiced concern about the difficulty of proving it.

He argued: “The new toy of American sports fans – betting on a multitude of sporting outcomes – is fundamentally different in golf to other sports in the country because of the proximity of galleries to stars. Even whispers prick the ears of competitors.”

However, golf has so far been seen as little risk for suspicious betting or match fixing. In the IBIA’s latest report, no alerts were issued for the sport, which compared to 19 for football, 14 for tennis, eight for table tennis, five for darts and one each for boxing, bowls, esports and badminton.

See also: FIFA finds no suspicious betting on Women’s World Cup