History: The New York City Subway, United States

In addition, any musician/entertainer may perform in subway mezzanines and platforms. On platforms, there may be no amplifications as this is part of MTA policies:
“The New York City Transit (NYCT) is a subdivision of the Metropolitan Transportation Authority (MTA) that operates the city's subways and buses. The NYCT authorizes these types of free expression in subway stations: "Public speaking; distribution of written materials; solicitation for charitable, religious or political causes; and artist performances, including the acceptance of donations.”
Performers must not be within 25 feet (7.6 m) of a token booth or 50 feet (15 m) from a MTA office/tower, blocking access to an escalator, stairwell, or elevator, interfering with transit services or passenger movement; or in an area where construction is occurring. In addition, performance is prohibited during public service announcements and may be no louder than 85 dBA at 5 feet (1.5 m) away or 70 dBa at 2 feet (0.61 m) from a token booth. Performances are prohibited in subway cars.