Wow. A burlap bag? A strawman assertion if ever there was one. No wonder it is so difficult to have a rational discussion about blind testing.
For those that don't understand but who are interested and still reading this thread, a blind test in this case would not mean a literal blind fold over one's eyes. It means merely that one doesn't know if the source is analog or digital. One can have his/her eyes wide open and gaze upon anything he/she wishes, except one: the source.
Now if you've got another, better, more reliable, repeatable, way to conduct a comparison that does better to eliminate these biases, then not just the entire scientific community, but the entire world would love to hear (no pun intended) about it.
As an aside, since it is irrelevant to the subject of this thread, if you want to know about the scrim used by Dr. Olive in his blind speaker evaluation, including any possible undue influence it may have, well, he's a member of this forum and several others. I'm sure you can just ask him and he will gladly tell you.