I remember going to see "Champions" at the Woodbridge Riverside Theatre on a midweek afternoon, I deliberately arrived a few minutes late to avoid some of the pearl and dean ads, paid my money to a lady who gave me a funny look, at the time I had no idea why, then followed her through to the cinema, as she entered she turned on the lights, there was not a sole in the place, I sat down and she went to start the film. nobody else entered through out the show.
Anyway, relevant to the thread, at the intermission she entered the cinema, and I got personal service on the Ice cream, drinks front, It would have felt churlish not to buy something.