I went caving yesterday and the camera stayed at home. I think it would have been an awesome time taking pictures, but there was no way physically to take the camera. Also after doing it I don't think it would have stood a chance of surviving. My wife did bring her P&S which struggled with the lighting in the cave (headlamps and flashlights) and it didn't fare without some scratches on the LCD and some dust and muck on the lens, but it was in a small case and in another small bag most of the time.
So would you bring your camera? Bring a backup one you don't care about as much? Leave them all at home and just enjoy it?