It's not so surprising that singers can have nights where they are completely off, but what is extremely surprising is the fact that they decided to put out these performances as big DVD/CD releases. Surely they have other footage or can film several shows just to be safe! This is probably true for CIM especially. The problem is almost always James, he's the factor that makes or breaks the whole listening experience.
Well, they don't film every single night. They decide ahead of time when they want to film, and if it's not the best night for James, then there's nothing they can do. They already spent the money on the camera people and stuff, so it's not like they can say, "Well, too bad. I guess we'll just shelf this one."
But I think people really exaggerate. His performance on LAB and even OIALT was fine. Maybe not the most stellar, jam packed with improvised F#s, but it's not like some of the other bootlegs I've seen where his voice was just consistently cracking to a point where it's painful to listen to.