SOMERDALE -- When 11-year-old Matthew Dieterle played trumpet in the Somerdale Park School holiday concert, his father held a cell phone in the air so his mother, who was home, could hear him play.

When it was time for parent-teacher conferences, Laura Dieterle told her husband, David, what to ask their children's teachers. And for Matthew's first basketball game, David Dieterle had to cheer loud enough for both parents.

"It wasn't the same when my mom wasn't there rooting for me," Matthew said. "She always used to be there all the time, and now she can't come on school property. So yeah, it's tough."

In a move that some education law experts say may be the first of its kind, the Somerdale school board unanimously voted in September to ban Laura Dieterle, 37, from school grounds.

The board cited "health and safety reasons" and the district's attorney says that Dieterle has demonstrated "violent tendencies" after repeated confrontations with school staff.

But Laura Dieterle, who is a school crossing guard employed by the Somerdale Police Department, believes she is nothing more than an active parent who angered the district by asking about a lawsuit related to a sexual harassment complaint against the superintendent.

Two weeks ago, Dieterle sent a letter to the school board, which she hopes will be considered at a meeting Wednesday, promising to stay away from board meetings for the rest of the year if she's allowed to attend some activities.

"They're only little once, and this is the time they need us the most," Dieterle said, describing how she was even forbidden from dropping off medication for her 6-year-old daughter, Brittany.

In barring Dieterle, the district's attorney cites a ban, upheld last year by a federal judge, that limited a Shawnee High School father's presence at the Medford school after alleged threats to his son's wrestling coach.

In that case, the father could still attend his son's matches as long as he didn't speak to staff or students and notified school officials when he arrived and left.

"The only times I've seen where there's real outright bans on showing yourself at any school thing at all is when the person is a registered sex offender," said Tom Hutton, staff attorney for the School Boards Association in Washington, D.C.

Board attorney John Kennedy said Dieterle has been repeatedly confrontational with school staff and she failed to conduct herself in a "respectful or professional manner."

"And there was concern that she was doing this during school hours," said Kennedy, who represents the 470-student, one-school, K-8 district. "So there was concern with regard to the safety of not only the staff but the students."

The conflict between Dieterle and the school, documented in written warnings and legal threats from the superintendent and board attorney, reached a tipping point in November 2006, when the police were called.

Business Administrator Kelly Peters accused Dieterle of pulling off a storm drainpipe cover in front of the school. Dieterle said she saw the cover was loose over an open hole and, concerned about children's safety, she complained.

A confrontation followed, during which Dieterle called Peters a "wench," Peters told police.

No charges were filed at the time. Superintendent Debra Bruner warned Dieterle in a Nov. 6, 2006, letter that she could soon "lose all visiting privileges to our school."

Undeterred, Dieterle continued to attend board meetings to ask about a lawsuit against the district, board and superintendent filed by a former buildings and grounds supervisor, Joseph Fallon Jr.

Fallon claimed he was fired in 2003 in retaliation for a sexual harassment grievance he filed against Bruner claiming she repeatedly brushed her body against his and pet his arm.

The wrongful termination suit was settled in April and is sealed by the terms of the settlement, Kennedy said. Legal fees were $41,118.99. But, before it was settled, Dieterle made more than 75 copies of the lawsuit to pass out to residents.

And then in September, she did something she believes was the final straw that prompted the ban: She wrote about the case in white marker on three sides of her car, and then parked it at the building on the first day of school.

"I needed support from more people to ask, 'Why are we paying for this lawsuit? How can I trust my kids are safe?' " she said.

That same day, the district filed a criminal mischief charge against Dieterle for the drain pipe incident 10 months earlier, and demanded between $300 and $2,000 for repairs.

Dieterle pleaded guilty to a lesser nuisance charge, which she said she now regrets. The restitution matter is still in court.

By late September, the school board voted 6-0 to ban Dieterle from school property. Kennedy denies that Dieterle's constant questions about the lawsuit had anything to do with her banishment or the drain pipe charges. He said there was a "confrontation" but he declined to go into specifics.

One ally, neighbor Tom DiPaolo Jr., who blogs about Somerdale for courierpostonline.com, described Dieterle as a "wonderful" person and mother.

"She's passionate about her kids, she's passionate about what goes on at that school, but she's not a danger to anyone," DiPaolo said.