With all the equipment they can afford to keep around, and probably already have around anyway, I'm surprised that big stars doesn't record (on tape and video) the entire recording sessions where they they take an idea an through various experiments and tryous and beta demos and alpha demos and etc from scratch to finish work out a song. I remember hearing of some lawsuit against a writer of some successfull book where he was able to prove through a bunch of early and quite different scripts that he had written the whole thing himself. Or herself, whichever it was.