Yes, I totally agree with the challenges you describe. And certainly, there are always going to be further avenues of study, whatever the result. For instance

Yes, I totally agree with the challenges you describe. And certainly, there are always going to be further avenues of study, whatever the result. For instance, I'm certainly not a Reiki expert, but my understanding is that chakras play a role. One could perhaps narrow the study I described above by having one practitioner intentionally misplace the chakras, while keeping everything else constant, to study specifically whether those locations are indeed meaningful. If you wanted, you could also approach studying it from another direction, and try to measure the transfer of energy that supposedly occurs. There would be various ways to go about that. Obviously I seriously doubt that a rigorous experiment would actually show an energy transfer from the practitioner, but if it did, and no flaws could be found in the measurement techniques, that would be pretty interesting!