(a) No owner, proprietor, manager or agent of any theater, concert or music hall or assembly hall or of any building, auditorium or room used for public gatherings shall permit any person to occupy any aisle in any such theater, concert or music hall, assembly hall or other building used for such purpose, or permit any person to occupy the back or sides of any such building or room used for such purpose, to such an extent as to prevent the free and unobstructed passage to and from the entrance to any aisle or any of the exits in such place. The provisions of this subsection shall not apply to town halls which are on the ground floor.

(b) Before any performance or event at any theater, concert or music hall or assembly hall or at any building, auditorium or room used for public gatherings of more than one hundred persons, the owner, proprietor, manager or agent of such theater, hall, building, auditorium or room shall make a public announcement that describes the location of emergency exits.

(c) Any person who violates any provision of subsection (a) or (b) of this section shall be fined not more than fifty dollars.