It's safe to say that 11 a.m. classes at the University of Illinois next Friday — and there are 433 of them — might have a few empty seats.
That's when former President Barack Obama will be on campus, speaking to just over 1,000 students at Foellinger Auditorium, an address that will be live-streamed online to thousands more.
A measure of his popularity: The ticket lottery portal opened at 11 a.m. Thursday, and by the time it closed at 5 p.m. Friday, 22,611 students had signed up — for about 1,300 seats.
Some of those who don't get in are expected to gather outside to catch a glimpse of — or perhaps protest — the former president, or even fill TV viewing areas in the Illini Union and elsewhere as they did for the World Cup.
"I bet you'll have a little of everything," said campus spokeswoman Robin Kaler.
It's a big deal when any head of state, or former head of state, comes to campus, especially "someone our students have told us many times, for many years, they would really like to see on our campus," Kaler said.
On campus, 'a lot going on'
Student body President Walter Lindwall said most students are thrilled to have a U.S. president visit campus, though he wouldn't be surprised to see some protesters.
But the fact that the venue is small and not open to the general public — and that Obama isn't a sitting president — means life won't grind to a halt on Friday.
"It's so specific to campus," said Jayne DeLuce, president and CEO of Visit Champaign County.
Campus event planners, at least, have cleared their calendars. And ordinary citizens can expect to see some traffic impact on an already busy weekend — when the former president travels to and from Willard Airport, for example, if he flies into town.
Details of his itinerary and the program that day are still being worked out, with his staff tight-lipped about the preparations.
Obama is expected to arrive Friday and isn't traveling anywhere else in Illinois, according to his staff.
At this point, he hasn't scheduled any other events besides the speech at Foellinger and the private ceremony afterward to receive the Paul H. Douglas Award for Ethics in Government from the UI's Institute of Government and Public Affairs.
Obama's communications director, Katie Hill, said she couldn't share any details about logistics or security until the advance team has assessed the situation on the ground.
Foellinger will be closed part of the day Thursday and all day Friday in preparation for the speech, said Laura Wilhelm-Barr, director of special events for the chancellor's office.
Six classes are scheduled there on Fridays, and instructors were notified so they could make arrangements to move, reschedule or cancel them, officials said. That's not unusual for a major event of this scale, Kaler said.
At least one professor was able to move the class to another site, although it's difficult because Foellinger is one of the biggest lecture halls on campus, Wilhelm-Barr said.
Some wondered why Obama didn't choose a larger venue for his speech, such as State Farm Center, Krannert Center for the Performing Arts or Memorial Stadium.
Those venues do have other events next weekend that could have complicated setup for such a major event: concerts Wednesday (Counting Crows) and Friday night (Jake Owen) at State Farm Center, and a football game at the stadium Saturday. And the entire Krannert Center is being set up for its 50th anniversary celebration on Friday night.
"There's a lot going on. It's a hopping town," Wilhelm-Barr said.
Campus officials and Obama's staff declined to comment on the decision, other than saying the UI was willing to accommodate the president's preference if at all possible.
Hill said Thursday that Obama liked the idea of connecting with students during this visit.
Foellinger 'ready to go'
It's not clear yet who might introduce the president, or whether students or any other speakers will join him on stage.
When President Bill Clinton spoke at the Assembly Hall in 1998, his team chose the late Tony Clements, a comedian and former head of the UI Division of Campus Recreation, as his "front man" to warm up the crowd, DeLuce said.
Vice President Joe Biden asked the Marching Illini and other student leaders to join him when he spoke at the Campus Recreation Center East in 2015. They had taken an active role in the "It's On Us" campaign to prevent sexual assault on campus.
Those logistics were more complicated, because the entire facility had to shut down for the event and planners had to essentially create an auditorium in a gym.
"We had to build stands for students to sit in and the stage. Foellinger is just ready made," with seats, a stage, lighting and speakers, Wilhelm-Barr said. "It's historic and it's beautiful and it's ready to go."
Security for Obama's appearance will be tight, but it's a bit different now that he has left the White House, officials said.
In general, there's still Secret Service protection and security for ex-presidents, but "they treat them a little differently," Willard Airport Director Gene Cossey said Thursday.
Willard: No major disruptions
Cossey had yet to talk with Obama's team about the former president's visit this week — and couldn't share any security details if he had.
But he's been involved with presidential and ex-presidential visits before coming to the UI in 2015.
He worked at the Southwest Oregon Regional Airport in 2008 when former President Clinton came through town on a campaign stop for Hillary Clinton's presidential primary run; and he was in Cincinnati when Obama flew into town several times during the 2012 presidential campaign.
For a current president, authorities tend to close the airspace and the airport, for all intents and purposes, while he's there, Cossey said.
For a former president, the air space is typically closed while the plane was taking off and landing, but not otherwise.
Travelers should expect some delays in traffic while Obama is going back and forth to the aircraft, which they will likely keep relatively isolated, Cossey said. Flight departures could be delayed, and it may take longer to get in and out of the airport, he said.
But he doesn't expect any flights to be canceled. It helps that Willard is a regional airport, he said.
"If we were having a departure or landing every two minutes, it would be a totally different scenario," he said.
"For the most part, it'll be short periods of time while he's actually at the airport," he said.
Of course, if the security team believes there's a threat, they may close the air space and the airport entirely, he said.
Whether the public gets to see or shake hands with the former president at the airport depends on the situation and his own preference, Cossey said.
With some of today's divisions over politics and free speech playing out on college campuses, security could be a bigger issue, DeLuce said.
"I think security-wise, people still have to be very careful of that," she said. "I think you'll have additional security."
The Secret Service has met with local fire and police officials, coordinated through the UI, to plan logistics and security for the event, officials said.
For C-U, 'a great tribute'
The Champaign Police Department will be providing "secondary support" as needed, said city spokesman Jeff Hamilton, declining to provide any additional details for security reasons.
The city of Urbana had no advance knowledge of Obama's visit, according to Mayor Diane Marlin.
"It was kept under very close wraps," she said.
"We don't expect a significant impact on everyday business around town, except that more than a few employees may be watching his speech," she said.
DeLuce said the visit by a current or former president is a "boon" for businesses and the community in general.
"They could have chosen a lot of places for him to come," she said. "That's a great tribute to the community and what we offer."