Oh, and yesterday Gallowglas told me that he once got a proof back from CreateSpace that was gibberish! The file was fine, but they somehow managed to put it through the blender before getting it back to him.
You don't have to get a paper proof from them--in fact, it's cheaper if you don't (but not a lot cheaper--less than $20). I've always opted for the paper proof because 1. I am compulsive, 2. sometimes things that look fine on flat sheets don't look fine in a bound book with a gutter. But I was wondering if the printing process was still as fraught with peril as it used to be. And the answer apparently is: Oh, yes.