I remember that for ... it was Sister Act, I think, they said that nuns didn't wanted to be taken in picture and that the pope didn't wanted to hear anything else that choir's music (so no cellphones) ! This one was funny!
But also, for "Dance of the Vampires", they said (for the pictures), that the vampires were really sensitive to lights, especially lights from cameras! And for the rings they said they hate listening to little noise... and if we don't respect that, ... we will never get out of the theatre !!
Yeah, also for Les Miz : "During French Revolution, nobody knew what were cameras and cellphones, so do not affraid the characters by showing them something they don't know in 1789..."
I LOVE pre-show announcements ! :)