Seven patriots protested against the May Day march at the Federal Building in downtown San Diego. No violence took place. One of the protesters was arrested, reportedly because she had a selfie stick. On the Marxist/La Raza side, one person was carrying a huge, wooden club. Two people had Mexican flags on staffs nearly the size of baseball bats. The police went after the person with the club, but stopped before wading into the crowd.
Those, who want to do this sort of thing, should make sure that the patriots are seen as expressing their freedom of speech and the other side is the aggressor trying to deny them their rights. Otherwise, they could be blamed for inciting a violent riot. In this case, the police appeared to identify the patriot counter protesters as potential "troublemakers." The patriots need to be able to argue they they are just defending their rights, not trying to instigate violence.
