What are the odds of a rogue NFL referee fixing games?
If it happened, would anyone find out?
NBA referee Tim Donaghy's implication in a betting scandal has given other leagues, including the NFL, reason to review their own policies regulating game officials.
Yes, the NFL subjects game officials to background checks. The league bars officials from most forms of gambling. The league enlists law-enforcement veterans, many with FBI backgrounds, to escort its officiating crews between hotels and game sites and airports.
Officiating director Mike Pereira and his staff grade every official on every play based on observations gleaned from multiple angles. Instant replay provides another potential layer of protection.
And then, at some point, the league must trust its people.
"The safeguard comes with the integrity of the individual walking down the field thinking, 'This game is bigger than me,'" former NFL referee Jim Tunney said.
Tunney worked three Super Bowls during a three-decade career that ended in 1991. The former school principal and superintendent struggled to fathom how Donaghy's alleged misdeeds could have gone undetected. NBA and government officials said Donaghy bet on games and supplied gamblers with inside info.
"It is amazing to me that an NBA official could work 13 years for the league and this has never come out before," Tunney said.
With 66 fewer regular-season games per team, the NFL might be easier than the NBA to regulate. The league's larger viewing audiences dissect more plays from a wider array of camera angles, with a 45-second play clock providing ample time for slow-motion replays. Criticisms tend to focus on an official's competence.
"You don't realize the scrutiny under which NFL officials operate," said former NFL referee Terry Gierke, who retired from NFL officiating after the 2001 season. "Not only do you have the network coverage, you've got the game films shot from two angles and then you also have NFL Films."
Tunney described a level of internal scrutiny designed to shield game officials from outside influences: "As an NFL official, it's like walking into a hotel lobby with the FBI guy with a newspaper in front of him and he drops the newspaper and he's watching you all the time."
The NFL benefits from fundamental differences between football and basketball, Tunney and Gierke said. Seven officials work each NFL game, four more than in the NBA. Each official has specific duties that diminish his impact on other areas of the game. Football crews also call fewer violations per game.
"It would be hard for a guy to affect a game in the NFL," Gierke said.
Gierke, now a real estate agent in Oregon, said no one had approached him seeking to compromise his integrity during 22 years as an official.
"Every year they bring in people from NFL security and they come in and spend hours talking about just that type of thing -- your associations, people that you don't know," Gierke said. "If you've ever got a situation, you are told to immediately contact those people and let them look into that. It's a constant thing every year that is highly stressed."
A 1989 book by investigative reporter Dan Moldea accused NFL security directors of using their law-enforcement ties to derail investigations into potential gambling scandals.
The NFL has generally avoided allegations of corruption among game officials in recent years.
"We do regular background checks on all officials and maintain extensive contacts in the gambling community and law enforcement to monitor what is taking place," a league spokesman said in an e-mail.
The league declined to make Milt Ahlerich, its security director and a former FBI agent, or Pereira, its director of officiating, available to comment for this story.
Pereira oversees game officials' on-field performance. Ahlerich's office conducts background checks on officials every three or four years, the league said.
The NFL's labor agreement with officials prohibits them from betting on sports or visiting gambling establishments during the season. During offseason months, officials must report to the NFL within 24 hours of all visits to gambling establishments. Rules prohibit officials from betting on team sports or associating with people the league identifies as gamblers.
Entering a gambling establishment during the season could result in a one-game suspension for first-time offenders. Additional offenses would subject an official to harsher penalties.
Gambling on a team sport would result in termination. The league could fine officials up to $1,000 for failing to report offseason visits to gambling establishments. Fines would increase with subsequent violations.
"There is not much you can get away with, and why would you want to do it, anyway?" Tunney said. "Why would somebody jeopardize not only themselves but the sport? That just appalls me."
Mike Sando covers the NFL for ESPN.com.