BBBW - did you not see that whole orchestra sitting behind them?
"This table, he is over one hundred years old. If I could, I would take an old gramophone needle and run it along the surface of the wood. To hear the music of the voices. All that was said." - Doug Wright, I Am My Own Wife
Or the three cast members doing nothing but "Aaaahhh..." behind her.
Nothing matters but knowing nothing matters. ~ Wicked
Everything in life is only for now. ~ Avenue Q
There is no future, there is no past. I live this moment as my last. ~ Rent
Actually I didn't see an orchestra as I wasn't that close and was only passing through... But not all the shows use the live band (especially the "rock" shows) and she was singing to a recording.
True...I specifically remember the conductor and musicians resting during her number. I believe a handful of other shows used a pre-rec orchestra track as well.