"If one doesn't know the identity, then at least we can narrow down the
reported reaction to (1) the sound, (2) the reviewer's mood or other
random neuronal firing."

How would we know which is which? When people were told in a listening
alone blind test that switching was used and in fact one bit of gear was
active at all times, when the switch was said to have happened the reports
of the typical subjective reactions switched accordingly. I think this
goes a long way in answer to the question. Blinded listening to one bit
of
gear and recording reactions does not remove the creation of perceptions
formed in the brain. When sighted, the perceptions are not random but
formed from existing patterns.