There are many ways to enforce a strike, and they depend on the context, the union, and it’s internal legitimacy. First of all, in Quebec, we usually vote on the strike ahead of time. So there is a few days between the strike GA and the strike day. During that period, it is important to make mass mobilization with posters and flyers to inform the students that a strike has been voted on democratically. When doing so, it’s also important to make sure that the flyers talk about the strike in an affirmative way, such as: “On X day, we will be on strike. There will be no classes.” The important thing is that anti-strike students simply don’t show up because they believe that classes will be canceled and that pro-strike students enforce the strike and participate in the events.
On the day of the strike, you need to have a mass of pro-strike students in order to enforce the strike. A badly enforced strike encourages anti-strike students to disrespect strike votes in the future.
So, if the strike is voted for a whole campus, the best way to enforce it is simply to make picket lines at the building door. This works well for campuses under 7000 students. If teachers are unionized, they may refuse to cross the picket lines (depending on the nature of their union’s contract) and classes will be canceled. In order to prevent confrontation on the picket lines, the administration of the campus might even cancel the classes themselves.
If the strike is voted on in a specific department, then it becomes impossible to blockade the building because courses are most likely to be scattered and mixed in different buildings. Courses may need to be picketed or disturbed separately. Some student unions in Quebec prefer to make small picket lines in front of the classrooms just before the class. Usually a symbolic 2 or 3 student picket line per door is enough to prevent the teacher from entering the class. Other student unions make “strike enforcement teams” that goes from class to class to disturb them until the teacher quits.
When enforcing the strike, it’s important not to be aggressive at first. Most students who will show up for their classes won’t understand what’s happening. Taking five minutes to explain what’s happening is usually enough to convince them to leave. Consider this as an opportunity to talk to students who are generally more apathetic.