I remember during the late 50's or early 60's the Celtics used to play pre season games or exhibitions in high school gymnasiums with plenty of seats available.. Jerry West, Bill Russell, Elgin Baylor et al. They played at Rogers High School in the late 50's or early 60's there were plenty of seats available..
This was on the heals of the Eastern States Catholic Invitational Tournament, ESCIT, with great HS teams like Power Memorial(Lew Alcindor), DeMatha, Trenton Catholic and some of the Boston Catholic HS Teams . It was a lot of fun to watch.. of course my Alma Mater, De La Salle Academy played as well although not that well compared to those powerhouses.