And of course you should boo. Why not? Well, because people will stare at you, because booing is still unusual behavior, looked on as extreme. But I think you should do it anyway. After the first movement! As soon as you know you hate the performance!
In the classical music world I'd like to see, there would be no problem if you did that. Everybody in the audience would expect very vocal reactions. So if you booed and others loved what they were hearing, they'd cheer. And everyone would just fight it out. I'd love to be at a performance where that happened.
Throwing a durian, though, would be cruel and unusual punishment for the offending musicians -- or, more likely, unless Roger Clemens is throwing one, for the poor souls in the audience that the durian actually lands on. I've had the pleasure of eating one. What a strange experience. A rare occasion in which "hold your nose" isn't advice to save us from ugliness, but instead a way of pointing toawrd a gateway to pleasure.
Feel free to quote any or all of this in your blog!
It's time for me to add here that I've booed a few singers who gave substandard performances at the opera. In most cases, people around me were cheering wildly. I would have to go through the SFO annals for the past decade to figure out exactly who so disgusted me. I've also walked out of a couple of performances, one of them mid-act, that for one reason or another were so bad I couldn't take it. (That's a subject for a different blog posting, however, because a couple of walk-outs had more to do with my mood of the moment than with what was on stage. I deeply regret at least one of them.)