(a) No person shall participate with four or more others in a course of disorderly conduct in violation of Section 509.03:
(1) With purpose to commit or facilitate the commission of a misdemeanor, other than disorderly conduct;
(2) With purpose to intimidate a public official or employee into taking or refraining from official action, or with purpose to hinder, impede or obstruct a function of government;
(3) With purpose to hinder, impede or obstruct the orderly process of administration or instruction at an educational institution, or to interfere with or disrupt lawful activities carried on at such institution.
(b) No person shall participate with four or more others with purpose to do an act with unlawful force or violence, even though such act might otherwise be lawful.
(c) Whoever violates this section is guilty of riot, a misdemeanor of the first degree.