Passenger Lauren Borgas, 26, said she was one of the passengers "red-stickered" by authorities, and was taken to a room where St John staff took her temperature and pulse.
"They said my temperature was up. Well yeah, that's because I was panicking, I had a mask on ... some people had masks, some people didn't. It was just chaotic."
Ms Borgas said that when she was eventually cleared to join the other passengers in a holding room she was surprised to see the Hitchi Senior Technical High School group among them.
"We said to the pilots, who were standing outside the door, 'Why are the school kids in there?' ... then another lady came running through and said, 'Get these kids out of here.'
"She took them out into the other room, but it was already too late, we had already mixed together," Ms Borgas said.
Later, as she left the airport about 12.15pm, her mother, Rhonda Borgas, was still on edge about what passengers might have been exposed to.
"If it was something really contagious, it just proves we're not ready to cope."
But Auckland Regional Public Health Service clinical director Dr Julia Peters defended the response and said the room mix-up had not posed a real danger to passengers.
"Some of the students did briefly go into the wrong room, but they were soon redirected into the triage area," Dr Peters said. "They were all masked. There was no risk to anybody in the room ... they were quickly removed from that area."
When the school group, some wearing masks, finally exited customs yesterday, there were comical scenes as they wove through a large media contingent.
Many gave their best one or two-word answers to questions, while others flashed peace signs and took their own photos of the media.
Stuart Cundy, who is organising the students' accommodation through Let's Homestay, said he felt the quarantine was something of an overreaction to minor symptoms.