PHOENIX -- Before the Oakland Raiders play their first game in Las Vegas, the NFL will change a pretty important rule.

For the first time, the league will allow referees and other on-field officials into the city.

Yes, you read that correctly.

To guard against even the appearance of a conflict, the league has for decades prohibited its officials from visiting Las Vegas at any point during the season -- with the exception of personal emergencies or mandatory meetings for their non-NFL jobs. They are allowed to visit in the offseason, provided they inform the NFL office. But even then, they are barred from sportsbooks.

Raiders to Vegas NFL owners approved the Oakland Raiders' move to Las Vegas on Monday at the league meetings. Owners voted 31-1 in favor of the move, with only the Dolphins voting against. Read more | Video • FAQ: Is Vegas market size a concern?

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Obviously, the in-season ban will have to be lifted since the Raiders' move to Las Vegas was approved 31-1 on Monday. As the league opened its 2017 owners meetings, the current policy was a reminder that Vegas-style gambling remains an important subplot despite the NFL's clear evolution on the issue.

As the NBA learned in 2007 with referee Tim Donaghy, the most efficient way for gamblers to fix a game is through the officials who administrate them on a play-by-play basis. That's part of why the NFL historically has gone to great lengths to protect its officials from exposure and avoid even the perception of meaningful contact.

Owners obviously are no longer fearful of placing a team within a sports gambling mecca -- a public stadium contribution of $750 million plus $200 million for maintenance has a way of changing minds -- but that doesn't mean they have dropped their concern about it entirely.

In fact, according to Green Bay Packers CEO Mark Murphy, the issue was likely to come up during Monday's meeting.

"I do think that's something we'll discuss," Murphy said, "and [go over] what kind of precautions are going to be taken to ensure that we don't have a major scandal coming out of having a team in Las Vegas."

During most of its history, the NFL's stance on Las Vegas always was clear: No way. But the recent growth of online gambling, Murphy said, largely destroyed the geographical boundaries the league was trying to maintain. Sports gambling isn't just available in Las Vegas.

"Gambling," Murphy said, "is an issue everywhere."

The point here is that the NFL hasn't relaxed its previously didactic views on gambling as much as it has recognized a changing landscape. There are still people within the league who are uncomfortable with the potential for a "major scandal" with a team located so close to the country's geographic sports-betting center, enough that as late as the 2016 season, officials' travel there was substantially limited.

That particular restriction will now have to be changed. The league is moving to a city whose primary industry it has long shunned. But as we sit on what feels like a major turning point in league history, it's important to remember the NFL's responsibility to maintain the credibility of its games -- because its officials will soon be allowed into America's Sin City.