“Mopping the floor after every strike is supposed to symbolize the completion of a show and the allowance of another one to be built on the same place. That and it makes everything all shiny and such.”
This cleansing ritual is used as a transition between shows performed in the same theatre. In my high school, the honor was only performed by seniors, but in the informant’s theatre it is open to anyone and everyone who wants to help ease the transition between shows and mark the liminal phase. It probably started out of the necessity of cleanliness, and stuck around as a transition ritual.