Mass shootings have generated a wave of anti-gun activism, and the Feb. 14 attack in Broward County, Florida, has been no exception.

The "March for Our Lives" movement has generated wide media coverage, school walk-outs and anti-gun rallies across the country, highlighted by the demonstration attended by tens of thousands in Washington last month.

It's also created instant celebrities, such as Parkland, Florida, student David Hogg, who's made a name for himself on television and social media for his demand for gun control.

But parents in one school district say that while they recognize free-speech rights, the district is going too far in endorsing gun-control and facilitating protests.

TRENDING: 'Greater shakings': Jonathan Cahn foresaw 2020 trouble, warns of even more

The non-profit law firm Freedom X has written to the Loma Prieta Unified School District, which includes the tiny city of Los Gatos in Silicon Valley, concerning an abrupt policy change that violates the law.

A letter on behalf of parents of students in the district warns of legal action if officials carry out their plan to allow students, faculty and staff to participate in a planned walkout April 20.

Freedom X wrote to Supt. Corey Kidwell asking for assurances the district will not help run the walkout in violation of its own policies.

The April 20 event, Freedom X explains, is being facilitated by "left-wing political activist groups, including the Network for Public Education Action, to influence gun legislation and is intended to indoctrinate impressionable school children as a scheme to push an anti-2nd Amendment political agenda."

April 20 is the anniversary of the Columbine High School shooting.

Freedom X represents parents "who object to their children having to participate or be shamed into participating in the politically driven walkout."

Bill Becker, Freedom X founder, said public schools are being used by anti-gun advocacy groups to push a political agenda inconsistent with the role of public education.

The letter first praises Kidwell and the district for announcing plans to treat any walkout as an unexcused absence.

However, the letter charges, that policy abruptly changed.

Freedom X said that "in violation of the California Code of Education 48205," teachers "were told to not run regular graded classwork, students and families were told there would be no academic or disciplinary consequences."

"You appeared to lead the walkout in solidarity with the political views expressed by one side of the gun controversy, and the district departed from lawful and constitutional protocols and procedures."

Despite the political activism of the Network for Public Education Action, the district "violates canons of free speech guarantees when it engages in any kind of viewpoint-based conduct that establishes an endorsement of one political viewpoint on matters of public concern," the letter says.

The coming protest is "nothing more than a politically organized scheme to influence and indoctrinate impressionable youth."

Explains the letter: "There can be no dispute that the April 20 walkout has nothing to do with the district's educational mission. Because the walkout is not authorized by education policy in California, and because it is viewpoint-based, we demand that the district publicly distance itself from planning and participation in it. The district must enforce its current policy disallowing the interruption of the school day."

Freedom X said that in another California school district "there has been talking of testing its ideological neutrality by staging a pro-life walkout."

"And just this week students in Colorado who support the Second Amendment staged their own walkout to counter the pro-gun control rallies taking place across the nation," the letter said. "These distractions from the educational mission of public schools is a manifest lesson in just how polarizing things are likely to become if leadership fails to take constructive action."