I've heard of plenty of opera singers who throw temper tantrums, but never one who does it second-hand the way Camilla does in my story. I made that part up because it seemed like fun. Still, I wouldn't be shocked to learn that there are real-world parallels; divas-the Italian word litarally translates as goddesses, but is used as a designation for operatic prima donnas ("first ladies"), which is to say leading sopranos-are pretty well known for their devotion to public attention.
And programs do matter to some singers, as well as other performers. There's a story from years ago involving tenor Giuseppe di Stefano. He was to do a concert when he suddenly got a gander at the program, which included several paid advertisements, one of them promoting a recording by rival Mario del Monaco, touting del Monaco as "the greatest tenor in the world." Di Stefano supposedly refused to perform if the program was passed out to the audience, and it wasn't; that particular concert went on with no program at all. I don't know whether or not that's a true story, but it reflects the egos that flourish in the opera world. (The famous "three tenors" concerts were the first time in my recollection that artists with this rarest of male voices were able to set aside their sometimes bitter rivalries and share a stage with each other. Even then the rivalry wasn't entirely abandoned; remember Jose Carreras and Placido Domingo getting together to mock Luciano Pavarotti's show-off vocal turn in the song "O Sole Mio?" It was partly in fun, and all three singers treated it that way on the stage, but many of the clashes between singers of the past were regarded much more seriously by those involved. The Hatfields and the McCoys were good buddies by comparison with the way some opera singers regarded their competitors.)
If you're an experienced theater-goer you've probably encountered performances where the program was amended with an insert such as I describe, correcting a cast member's name. I'm not sure I've heard of a newspaper reviewer overlooking the insert, but there have been plenty of published reviews with all sorts of errors, so this isn't that far-fetched. And reviews do indeed matter to anyone who performs on a stage, whether operatic or other, and can have a significant impact on their careers.