A gun openly carried by a spectator at a school concert in 2015 has turned into a major legal case as the Michigan Supreme Court considers whether the state's public schools can trump the Legislature and adopt their own restrictions on firearms.

The case from Ann Arbor has been on the court's docket for more than a year. But arguments set for Wednesday are getting extra attention in the wake of a Florida school shooting in February that killed 17.

There's no dispute that Michigan law bars people from possessing a gun inside a weapon-free school zone. But there's a wrinkle: Someone with a concealed pistol permit can enter school property with a gun that's openly holstered.

Though rare, it happened three years ago at a choir concert at Ann Arbor Pioneer High School, scaring teens, staff and spectators. The school board responded by banning all guns, with exceptions for police.

"If a student were to bring a gun into a school, that would be worthy of an expulsion," said Jeanice Kerr Swift, superintendent of Ann Arbor schools. "So why would it be different for other folks? ... What this case is about is local communities having a choice."

Separately, the Clio district, north of Flint, has a similar policy. The Supreme Court is hearing challenges from gun owners in both communities.

Gun-rights advocates argue that local governments, including elected school boards, can't step into an area reserved for the Michigan Legislature under state law. They point to a Lansing-area library whose ban on the open display of guns was struck down by the state appeals court in 2012.

But in Ann Arbor and Clio, another three-judge panel at the appeals court said schools are in a different category and have freedom to further restrict guns. The districts won that round.

Ken Herman, a paramedic and gun-owning parent who sued the Clio district, believes the appeals court got it wrong. In a filing at the Supreme Court, his attorney said schools have a duty to keep students safe, but lawmakers have "chosen to reserve the power to regulate the possession of firearms."

Herman, 36, said he carries a gun for protection wherever it's allowed. He said fears would be eased if more adults educated kids about proper gun ownership.