Ken Bloom, Show and Tell: The New Book of Broadway Anecdotes (New York: Oxford University Press, 2016), 226-7.
Here’s a kinder but no less devious prank that took place at Paper Mill [Playhouse in Milburn, New Jersey]. While rehearsing Damn Yankees, director George Abbott was having a hard time staging the courtroom scene in Act Two so that the entire cast could be seen from all angles. It had to be so exact that there were marks on the stage for placement of all the chairs. One of the ladies in the show, we’ll call her Roberta, had been in a lot of shows with Fred, and it was always expected that he would pull some practical joke or another.
Her chair was blocked to be just right of center. Every night, Fred would imperceptibly move her mark a little bit farther to the right. Little by little, quarter inch by quarter inch, her seat was moved closer and closer to the wings. The movement was so slight, Roberta never noticed, even though she was always on the lookout for Fred to pull something. Actors are so agreeable, so used to following the directors’ orders, they think, “If that’s where the mark is, that’s where I’ll sit.” By the end of the run, her seat was halfway offstage until only her knees were visible to the audience. On closing night, Fred moved the mark back to where it had started, many feet toward the center of the stage. Roberta immediately grasped what Fred had done, and all through the scene she was shooting daggers from her eyes at him.