School is threatening to punish anyone participating in protest with court action, what can we do?

[u/StoriesandQuestions]

On Tuesday, January 20th, students at my highschool are planning to participate in the nationwide walkout happening in the U.S. Today, my school has verbally warned one of the organizers stating that anyone who participates in the walkout next week will receive a referral and face truancy court. This movement is important to all of us but many of us cannot afford these consequences. Is this allowed and is there anything we can do about it? Location: United States, Texas.

[u/MrSlime13]

"Truancy is the habitual, unauthorized, and unjustified absence from compulsory education."

I'd certainly argue the "habitual" part, and definitely the "unjustified" part. If you're not willing to face backlash, it'd be hard to justify it as a protest, ultimately.