It's not just boring, it's stressful as well. I've done it (not for break-in). My results were null but as soon as I got back to unstressed listening the results were obvious. I've read that being a test subject is a learned skill and that untrained observers are unreliable because the testing procedures themselves hide some of what might actually be there. Having experienced the heightened stress of testing I can believe this. Needing to practice and hone my skill as a subject is yet another strike against me trying to prove anything.
Again, if nobody can make a claim without supporting data, AC is going to have tumbleweeds blowing through. Deadwood.
Whether we choose to believe the viewpoints of many saying "I hear" or those who say "you shouldn't" is up to each observer.