As Yale parents arrived on campus to learn about college life this weekend, several union members, retired Yale workers, and undergraduates tried to make sure the parents learned something about the University’s labor relations as well.

About 25 union supporters distributed fliers criticizing Yale’s pension plan at Woolsey Hall Saturday morning as parents arrived for a panel on education, and two undergraduates who were distributing fliers inside Woolsey Hall were detained by Yale University Police.

Pensions are among the many issues under dispute as Yale and its two largest unions, locals 34 and 35, continue contract negotiations.

The contracts for locals 34 and 35 expired in January. Yale and its unions have been negotiating new contracts since February. Locals 34 and 35 represent nearly 4,000 clerical, technical, service, dining hall and maintenance workers.

The leaflets contained information about the University’s pension benefits to recent retirees and workers currently expecting to retire. In the leaflets, organizers said pensions were the most important issue to union members who are seeking a resolution to current contract talks.

Union spokeswoman Deborah Chernoff said Saturday’s event was intended to emphasize the importance of pensions to Yale workers and to show the human side of the issue.

“The people who’ve already retired are in some ways a cautionary tale,” she said.

Chernoff added that though the pension issue has not been given much attention in negotiations, it continues to be one of the most important issues to members of the unions.

“I think most people realize that this is the best opportunity for workers at Yale to make a difference in their pensions,” she said.

Yale President Richard Levin declined to comment on the event.

While the retirees stood outside both entrances to Woolsey, a few undergraduates passed out information about labor relations on campus inside the building.

Alek Felstiner ’04 and Thomas Frampton ’06 said they originally arrived at Woolsey to hand out leaflets advertising a panel for parents that was to be held on Beinecke Plaza. The event — called “Education, Labor, and Responsible Citizenship” — was cancelled because of rain but the two students continued to distribute information. But Frampton said that while they were passing out fliers in the hallway outside the Woolsey auditorium, several policemen began threatening to escort them out of the building and eventually detained them for about 15 to 20 minutes in the Woolsey rotunda.

Felstiner and Frampton said they thought they were detained because of the information they were distributing concerned union issues. Yale Police could not be reached for comment this weekend.

“It was a really frustrating experience,” Frampton said. “I kind of assumed basic free speech was allowed on campus.”

Felstiner said he went to Woolsey Hall with his father to distribute leaflets about the educational and social impact of past labor strikes at Yale before attending the education panel.

“Considering that we were exercising free speech on campus — this was shocking and discouraging,” Felstiner said.

Frampton and Felstiner both said their experience made the recent arrests at Yale-New Haven Hospital more personal.

“I was disappointed to see the trend of curtailing free speech extend to undergraduates,” Felstiner said.

Last month, Yale-New Haven Hospital police arrested two graduate student researchers and six members of Local 34 for distributing leaflets outside the hospital. Union leaders said the arrests were meant to scare potential union supporters. Hospital officials said the workers were arrested because they were blocking entrances.