I don't think you'd have any problem getting the stage or police protection. Still, I understand that what you're describing would be awful. But it doesn't allow the university to punish an individual based on their out-of-classroom speech. Two wrongs don't make a right.
How should universities proceed when it comes to professors who give assignments to attend political “protests”? Or professors who change class location to an anti Israel encampment? Or professors who cancel class so they can attend and encourage students to attend? Or professors who canceled finals so the class can attend? Each one of these examples occurred. Some more than others. Each example infringes on the 1A rights of students/families/taxpayers who have different positions.