Danielle Brinkman was a model student at Rowland High School (search) — straight A's, perfect attendance since kindergarten and a member of the choir. So her teachers and fellow students were shocked when she was expelled for bringing a knife to school.

Brinkman didn't use the knife on anyone, but school officials say she violated the zero-tolerance policy (search) and came down hard on the high school junior, tossing her out for being a danger to her classmates.

"We still had what we considered to be a very serious offense," said school Superintendent Maria Ott. "We have to look at the entire student body and look at what we believe in that particular case is the appropriate action to take."

Brinkman says she woke up late for school and put on her work pants, which had a knife in the front pocket that she uses to open boxes at her supermarket job. She says administrators overreacted.

"I didn't expect that," she said. "It seemed so harsh for something that was important, but it … I didn't kill anybody, you know."

Her parents agreed, saying the punishment didn't fit the crime. After their daughter was transferred to another high school and went through a long legal battle, the court finally sided with the Brinkmans and allowed her to return to Rowland.

California is among the many states that have enacted stricter school violence-related standards because of the spate of school shootings in recent years — like the 1999 Columbine massacre (search) in Colorado. But, critics say, sometimes the rules go too far.

Click in the video box near the top of the story to watch a full report by FOX News' Anita Vogel.