Many students excited to add their voices to the movement are unsure how far they can push, but are forging ahead without help from trusted teachers, who are often prohibited from political activity by school codes.

And while colleges from Illinois State University to DePaul University are spreading the word that punishments received as part of this movement will not affect students’ chances of admission, internet experts warn that a simple selfie from a walkout posted online could be reused or, worse, repurposed in ways the student can’t control.

“There aren’t a lot of really simple words of advice that I can give in a sentence or two,” said Rebecca Glenberg, senior staff attorney at the ACLU-Illinois. To offer some direction, the national ACLU office on Thursday hosted a “Know Your Rights Training” conference call for students across the U.S. to offer guidance about free speech and expression in a school setting.