A parade of college students marched through the Municipal Courts Building yesterday to explain why they were caught up in mass arrests following the G-20 summit, and District Judge Kevin E. Cooper played the role of a scolding parent.

"Young lady, you made a bad judgment," he told Jocelyn Petyak, 21, a Pitt senior who was arrested on the night of Sept. 25 in Oakland and charged with failure to disperse and disorderly conduct. "You should have left your friends and gotten your butt out of there."

The judge then asked about her grades.

"I have a 3.4 GPA," she replied.

"Give me 25 hours of community service," he said. "I'll dismiss the charges."

Police made nearly 200 arrests during the summit last month, and 103 cases had hearings yesterday. The vast majority involved minor charges, but at least four people were held for trial on felonies, including a man accused of hitting a police officer with a brick and another man who was accused of taunting a police K-9 while dressed as a cow.

By 8:30 a.m., a line stretched out the front of the courthouse as G-20 arrestees passed through metal detectors and tried to locate their lawyers. On the second floor, dozens of people swarmed around representatives from the offices of the county district attorney and public defender, trying to cut deals and clear their records.

By the end of the day, 53 people had agreed to perform community service in exchange for having the charges dismissed.

Hearings took place simultaneously in three courtrooms.

"It's sort of organized chaos," said Mike Healey, an attorney for five people who appeared before Judge Cooper.

The judge dismissed charges against two of his clients, Nicholas Brooks and Joanne Ong, and ordered three -- Melissa Hill, Amith Gupta and Thomas Judd -- to pay fines of $300.

Judge Cooper was willing to acknowledge the varying circumstances of people who were still in the streets after police had ordered the dispersal of a large crowd gathered in Schenley Plaza on Sept. 25, hours after the summit had ended and world leaders had gone home.

"Nicholas, you appear to be a timid guy. You couldn't get out of there," he told Mr. Brooks, 18, who said he had been trying to return to his dorm when police arrested him. "I'm letting you off."

To Ms. Hill, a reporter from Minneapolis who came to Pittsburgh to cover the G-20 for Twin Cities Indymedia, he said, "You're a journalist, you should have known better."

Ms. Ong, 19, a Carnegie Mellon University student, teared up as she described her search for an escape route through lines of police in riot-control gear. The judge dismissed her charges.

Ms. Petyak, of Shadyside, accepted the community service mandate, but she was angered by the judge's verbal reprimand. She said it was "out of line" for him to tell her she should have abandoned her friends as police closed in.

Lt. Clarence E. Trapp testified that police officials decided to give the dispersal order at 10:42 p.m., after some protesters, who had gathered for a rally against police brutality, charged lines of officers. Some also threw bottles, Lt. Trapp said.

The order was blasted at least eight times from a Long-Range Acoustic Device, which can be heard up to a quarter-mile away. Officials decided to start making arrests at 11:07 p.m. Many people were apprehended on the lawn of the Cathedral of Learning after police encircled the area.

Molly Shea, 22, a student at Ohio University, came with nine other students to protest the summit, but she said she had just left a nearby coffee shop to look for friends when she was swept up in the Oakland arrests.

Police confiscated her laptop and never returned it, she said. Judge Cooper ordered her to stand trial on charges of disorderly conduct and failure to disperse, and she must return to Pittsburgh Dec. 29 for a formal arraignment.

Down the hall, District Judge Ron Costa heard cases involving more serious accusations, and he held three people for trial on charges of aggravated assault.

Trevor Burgess, 30, was arrested Sept. 24 at Baum Boulevard and Cypress Street after hitting Officer William Churilla with a brick, the officer testified yesterday. In addition to the assault charge, Mr. Burgess faces charges of inciting a riot, failure to disperse and propulsion of missiles and possessing the instrument of a crime.

Lauren Wasson, 23, of Garfield, is accused of striking Officer Shawn Dady with her bicycle in Oakland on Sept. 24.

Banu Quadir was arrested nearby the same night by Officer Michelle Auge, who testified yesterday that Ms. Quadir struggled and hit her with an elbow. Both Ms. Quadir and Ms. Wasson were held for trial on assault charges.

Judge Costa ordered 22-year-old Kalan Sherrard to stand trial on a charge of inciting a riot after hearing testimony from Officer William Friburger, who said he saw Mr. Sherrard parading through the streets of Lawrenceville and Bloomfield on Sept. 24, wearing a cow suit with udders.

Mr. Sherrard was "banging his drum, flailing his arms, yelling and screaming," and he repeatedly taunted a police K-9, Officer Friburger said.

Video footage of Mr. Sherrard, a student at Oberlin College in Ohio, in his cow outfit was broadcast on Comedy Central's "The Daily Show."

"It was more to do something to make people look twice," he said before the hearing yesterday.

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