CHICAGO (CBS) — It’s the one part of Lollapalooza that few people saw until now — hundreds of young people rushing a fence and knocking it down, then running right past security.

As CBS 2’s Derrick Blakley reports, authorities have confirmed that there were no more than 30 arrests at Lollapalooza the entire weekend. And, despite the potential for injuries, police insisted it’s not their job to guard the gate at a private event.

“It happened multiple occasions, different times throughout the weekend – multiple locations,” said Jacob Thom, who volunteered at all three days of Lollapalooza.

Thom said large crowds gathered several times, charged the gates at Lollapalooza and simply rushed past security guards.

“There’s nothing you can do when you have five security guards, who most of the time just want to get out of the way,” Thom said.

The three-day music festival drew a record-setting crowd of more than 270,000 – many of whom paid upwards of $200 for a three-day pass.

Thom attended all three days of the fest as a volunteer.

He said that people could have been trampled and severely injured by the crowds of gate crashers.

“There was one incident, an ambulance came out afterwards because an old man had got crushed, just standing around, and severely concussioned, bleeding,” Thom said.

In YouTube video of one of the gate-crashing incidents, two police officers rushed up the stairs to end a stampede. But Police Supt. Garry McCarthy said Monday that guarding the gate isn’t their job.

“We’re there to provide for the public safety,” McCarthy said. “We don’t work as bouncers for admission purposes.”

The superintendent declined to comment on whether or not Lollapalooza officials had provided enough security for the festival.

Thom, who shot a gate-crashing video on his cell phone, said the real answer might be spreading out the crowds by spreading out the event.

“Perhaps having more after shows, more dispersed shows in different locations of the city, rather than one central location, might help,” Thom said. “If they had multiple parks … maybe the crowd would disperse easier.”

Thom’s thinking was that there are just too many people in too small an area for security to handle all the crowds. He said by spreading out the acts to other, smaller venues, it would make the shows easier to secure.

Mobs of gate crashers apparently used cell phones to coordinate their stampedes and gather the biggest numbers at the most poorly defended entrances.

But the people hurt the most were the lollapalooza’s organizers, who lost untold amounts of money to crowds of people crashing the gates. Organizers did not return calls for comment on the gate crashing incidents.