This is true, but I don't think it's that relevant to this. In terms of public science communication, presenting a failed test on its own, especially without acknowledging it in big bold letters upfront as a failure brought on by the tester's lack of competence in performing the test, is misleading at best. I would suggest that this test failed because it didn't actually test what it set out to test (the difference that pickups would make), but rather tested whether pickups wired incorrectly sound like pickups wired correctly (they don't).A failed test in science/engineering is very useful and valid and is a core part of the scientific method.