Something just occurred to me: how did people transmit their musical requests to orchestras?
Think of it: You're at a swank supper club in the 1920s, and you decide you want to hear "The Kashmiri Love Song." Whether you're dancing on the floor or eating at your table, how would you convey your request to the orchestra's conductor?
Even though you often hear about people in such situations MAKING requests, you rarely hear HOW. Did they politely mention the request to their waiter or a passing busboy? Did they shout it out while applauding? Did they approach the musicians during a break? Did they leave notes on the stage? Was there an established job of standing at the edge of the stage and taking requests?
My guess is that the waiter or busboy was the go-between, but I have no proof and I'm very curious.