Artists, musicians and performers are exercising their basic First Amendment rights in parks. The expressive matter rules violate these rights. The US Supreme court has ruled that: "Wherever the title of streets and parks may rest, they have immemorially been held in trust for the use of the public and, time out of mind, have been used for purposes of assembly, communicating thoughts between citizens, and discussing public questions. Such use of the streets and public places has, from ancient times, been a part of the privileges, immunities, rights and liberties of citizens."