As many as 3,000 people were uninvited at the last minute from Monday's ceremony with President Barack Obama honoring Latino labor activist Cesar Chavez in Keene, Calif.
The number of people who wanted to attend the event, in which Obama designated Chavez's former office and home as a national monument, overwhelmed organizers at the Cesar Chavez Foundation and the United Farm Workers union.
"We've never had this problem before," Cesar Chavez Foundation spokesman Marc Grossman told The Huffington Post. "Usually we have to encourage people to attend our events."
Event organizers from the Cesar Chavez Foundation and UFW realized they had a problem Friday morning, less than 48 hours after posting the signup form on their websites.
"The response was so overwhelming and quick that we realized it was far beyond our capacity," explained Grossman.
Signups on both websites were stopped before 9 a.m. Friday, but not before an estimated 2,000 to 3,000 people more than the event's 7,000 capacity had registered.
Both organizations decided to confront the problem indirectly at first, with two email blasts Friday and Saturday asking everyone who had already registered to re-register. The organizers also described the difficulties associated with travel, waiting times and Secret Service screenings, figuring 20 percent to 30 percent wouldn't re-register.
But Grossman said the emails resulted in "almost no drop-offs." At that point, event organizers began telling people they were uninvited.
From late Saturday to Sunday, the organizations sent emails to thousands who had re-registered for the event. They then followed up with dozens of volunteers calling late into the night Sunday to speak with the disinvited.
"There were those who were upset and understandably so," said Grossman. "All we could do was explain and apologize."
The disappointed spoke out angrily on Twitter.
Maricela Mares-Alatorre, a community activist from nearby Kettleman City, told the Los Angeles Times that she was "heartbroken" over the disappointing turn of events.
"We were uninvited Sunday night," said Mares-Alatorre to the Times. "They said they were overbooked. We’re heartbroken"
The three-acre Cesar Chavez national monument site includes a visitor's center, Chavez's preserved office, a memorial garden, and Chavez's gravesite. The grounds also include the house where Chavez lived for the last 22 years of his life. His wife, Helen Chavez, still lives there.
Beyond any memorial site or statue or street name, said Grossman, the greatest monument to Chavez's legacy is the ongoing fight for farmworkers' rights.
"Cesar said many times that if the union and the movement did not survive his death, then he would have felt his work was in vain," said Grossman, who was Chavez's former press secretary and personal aide. "The greatest monument to Cesar Chavez is to continue this movement," he added.