Tipple point

Cue for a drink ...
The Importance of Being Earnest
I went up to see Erica Whyman's production of The Importance of Being Earnest at the Oxford Playhouse. Not for the first time, I was glad to decant my half-drunk interval glass of red wine into a plastic cup for the third act (environmental guilt aside), and very pleasant it was too having a little something to nurse while the characters figured out what had happened to the contents of that handbag. It occurred to me that a tipple would often be just the thing to sort out the longueurs in, a Bruckner symphony, or a Verdi opera. Why is it perfectly acceptable to take booze into the theatre but not classical concerts or operas? I'm failing to see that there can be any difference whatsoever between these events ...