I have to say, we have only ever done this when we have had concerns about participants in our free tickets for young people - as much for the sensibilities of their parents as for the children. Despite John's argument, when a character has his throat cut and there is arterial spurt splattering the walls, an 8 year old could easily find that a bit disturbing, and so we warn parents. Otherwise, we don't issue such warnings, but companies and festivals do need to be careful these days because of the storms of protests that can be ignited by just a few people.
When we produced Aida last year, I can report that I must have received over 100 emails and letters complaining, in the most ferocious terms at times, about the content of the production. The key complaint was a party scene at which a couple of revellers snorted cocaine from the derriere of a woman in scanty underwear. The problem seemed to be more the drugs than the derriere.
However, it strikes me that what many of the people were really complaining about was the modern interpretation, and this is what often lies at the heart of these complaints. Audiences get very cross indeed when classics are updated, and the further inclusion of a bit of sex, or violence, is the icing on the cake that finally provokes the real fury; without the additional spice, there would often only be irritated indifference.
I have sympathy with Edinburgh inasmuch as they themselves were likely to have been hugely reluctant to issue a warning (unless they were cynically seeking sales) but would have felt, in the light of recent uproar, that they had to give the more puritanical opera audience a heads up.
One could argue that the mood of the market is thus, and so we should tread carefully at a time when sales are ever harder to come by. I have no doubt at all, for example, that a sizeable section of our audience were holding back on this year's season at OHP in order to at first discover the nature of our productions before committing. That is the way it is right now, so we should be careful before we condemn Edinburgh too firmly. Equally, we mustn't fall prey to the overt conservatism of certain sections of the audience and encourage them to spread their wings a bit.
But it is a fine line. Iris caused all sorts of outrage and offence, but nobody - at all - wrote to me to complain, because what we showed was precisely what was in there. Which I think supports, if only slightly, my argument that what offends is often more about changing the libretto's original period and setting (especially, in this case, because the audience don't really know the piece and have rarely seen it in any kind of setting, let alone the one we put it in).
If, for example, you set a Tosca bang in period and place, but make Tosca's murder of Scarpia visceral and realistic, with blood and guts splattering the stage, I doubt you'd get much objection. If she did it whilst wearing a tie-dyed shirt and a bandana, you'd never see the end of the emails. We should be a little more aware of this audience train of thought than we currently are.