By Dan Gilgoff and Dan Merica, CNN

(CNN) - The annual pilgrimage to Mecca, Saudi Arabia, is the world's largest gathering of Muslims - the biggest annual gathering of humanity, period.

So it's no surprise that Middle East experts expect this year's pilgrimage, the first to happen since the Arab Spring began last year, to be different.

The pilgrimage, called the Hajj, happens in the same global neighborhood as countries that have been roiled by protests, revolutions and war over the last 11 months.

But there's uncertainty about exactly how this Hajj, which officially begins Friday, will be different.

Some experts are watching for potential flare-ups in Saudi Arabia, a country governed by an unelected royal family and where freedoms are limited. They note that ordinary Saudis will be rubbing shoulders with Arabs making pilgrimages from countries that have staged anti-government demonstrations and have unseated long-entrenched regimes.

"This idea of freedom and dignity is spreading like wildfire, and at a gathering like the Hajj it's conceivable that the electricity coming from these ideas will be picked up," says Akbar Ahmed, the chair of Islamic Studies at American University. "This is what scares the Saudi bureaucracy."

"There are thousands of pilgrims who want to topple the established order of the Saudi monarchy," he says.

But Ahmed and others say the Hajj's effects on the Arab Spring are just as likely to be much broader, as many pilgrims share notes on uprisings and overthrows before returning home to countries ruled by despots.

"This is a venue where you can come into contact with hundreds of thousands of people, so for people who are coming from these newly liberated lands, it is a bit much to ask to say absolutely nothing about it," says Kelly Pemberton, an assistant professor at The George Washington University who studies Islamic reform movements.

"Many people are going to see this (Arab Spring) as a sign of God's favor," she says.

At the same time, experts on the region note that the Hajj is a solemn religious event that is physically and spiritually demanding and that affords little time for politicking, raising doubts in some scholars' minds about the magnitude of a Hajj effect on the Arab Spring.

The Saudis haven't announced special security measures for this year's Hajj.

But the event, which draws roughly 2.5 million pilgrims, has long been managed with military precision, and scholars say the government there has been preparing for months for its first Arab Spring-era Hajj.

"They'll be on guard for a flashpoint moment or a riot, something that flares up and becomes something," says Ahmed, referring to Saudi security forces. "In Tunisia, one man set himself on fire and three months later the Egyptian president is toppled."

There has been political violence during the Hajj in the past, most notably in the 1980s, on the heels of the Islamic Revolution in Iran.

Iranian leader Ayatollah Khomeini's followers attempted to disrupt the pilgrimage throughout the '80s, though their plots were repeatedly quashed by Saudi security forces.

In 1987, however, Iranian pilgrims incited a riot that killed more than 400 people, according to globalsecuity.org, a stark illustration of the rift between Shiite-ruled Iran and Sunni dominated Saudi Arabia.

Saudi Arabia has not seen the kind of protests now roiling countries like Syria, Yemen and Bahrain, but people there lack many basic freedoms. Political participation is limited.

The Saudi government has been politically sensitive to its people since the outset of the Arab Spring, spending billions on domestic programs aimed at improving the lot of its citizenry.

And scholars say that Saudi Arabia has supported anti-government forces in some Arab countries, including rebels in Libya and protestors in Syria.

"I can't image anybody is going to show up in Mecca denouncing the royal family," says Juan Cole, a Middle East specialist at the University of Michigan. "A lot of people going to Hajj will be connected with the (Egypt-based) Muslim Brotherhood, which has longstanding good relations with the Saudis."

Some experts speculate that Saudi Arabia, which tightly controls the numbers of pilgrims allowed to attend Hajj from each country, is reducing its quotas from certain politically unstable countries to curb the influence of would-be revolutionaries.

The U.S. embassies in Egypt and Tunisia, two countries that have seen their governments overthrown this year, did not immediately reply to requests Thursday for statistics on slots for pilgrims granted by Saudi Arabia.

Some scholars say the governments of other Arab countries are likely to be reducing the number of pilgrims allowed to attend Hajj in Saudi Arabia this year.

"The leaders of Syria, Yemen, Iran and Saudi Arabia are somewhat worried about the Hajj providing a forum for people to trade ideas and strategies and coming home to pick up protests and really find the momentum to get things going," says Pemberton of George Washington University.

Since late last year, some Muslim religious happenings in the Arab world have become forums for anti-government activity.

In Egypt, Friday afternoon prayers - the most significant prayers of the week for Muslims - served as catalysts for the biggest anti-government demonstrations of the revolution.

When Egyptian President Hosni Mubarak stepped down in Egypt, the announcement came on a Friday, hours after Egypt's Muslims had observed afternoon prayers.

In Libya, rebels reached a turning point in a six-month old civil during Ramadan of this year, when evening prayers at mosques helped ordinary people organize against Moammar Gadhafi's regime.

With Gadhafi dead, more Libyans may get to attend this year's Hajj than in years past. Other post-revolution Arab countries may send a more diverse mix of pilgrims.

"The biggest effect is the allocation of Hajj visas," said Asim Khwaja, a Harvard University professor specializing in international development. "Some countries did a lottery, some did rationing, and with the government changes, if countries were doing rationing in the past, you can imagine they were sending friends and officials."

"Now there may be a more egalitarian mix," Khwaja says. "This will be a more democratic Hajj for the Arab world."