NEVER, During an English Horn Solo!
To the guy who was siting diagonally across from me: I don’t know what you could’ve possibly found in the program that was more enthralling than the actual performance going on in front of you, nor do I care, but please do not keep noisily flipping your pages during a sonata where there are only two instruments playing. If you want to do this in Davies Symphony Hall, which seats thousands, during a loud Tchaikovsky passage, when the horns are braying away, no one will notice, and I won’t care (so long as you don’t do this during an English horn solo).
Of course some people don’t know the diff between English horn and French horn. Sad, but true.
I read it here.