The logical fallacy of blindtest, in audio or music, when they are used out of their narrow usefulness window function, to reveal the reality or deceptiveness of small change that are not evident at first, is that they suppose that a DEFINITIVE judgement is possible out of the normal context and habit where the judgement is produced usually...Like a violin stradivarius compared to a modern one...Or an audiophile assessing without stress a small change in his system in his room with his files...
The use of blindtest in statistical medical procedure is another story completely... It is there they reveal the most important facet of their power , eliminating the human biases from the medical experiment...But assessing the value of a violin ask to the player the exact opposite, a mastering of the instrument, using his experienced biases or learning personal experience, impossible in most improvised blindtest...The listeners also must be experienced and in his normal circonstances or near them....