That might work, except when people show up at the peaceful protest armed for action.
And if rioting and looting happen later in the evening when the hooligans come out, I would expect the police (and national guard if necessary) who have recieved the appropriate crowd control training to intervene to protect public safety and property. This is not a job for private citizens, especially when they travel from outside the area.
Lock em up.
Why "except" when people show up with gun? If they can legally carry them, it is, usually, not a problem. It is the people illegally carrying them that are usually the problem.
As for the remainder, the problem, as we have seen, is when the cops "stand down" and don't do their job. That is what led to the issue in Kenosha in the 1st place. The State's Attorney and the Chief Judge is currently why downtown Chicago is a shitshow.
And, if you had read up on it, you would know that the dumbass kid did have a connection to Kenosha.