I'm not a big fan of walking out of class at any time, and when college students have done it to demonstrate over an issue (usually rising tuition) I have not been pleased, but I do appreciate the political and speech aspect of protest and I like student initiative. If I was a guide for the walk out participants, I would have advised them to ask teachers to have a lesson related to the issue (varying based on subject) and organize a mass demonstration on the weekend or evening. I hate to be cynical, but I will. It's easier to ask students to join if academic time rather than personal time is being sacrificed.