prosperity,
Hi.
Confidentiality is primarily about 'harm' that might occur if information about someone were 'made public'. Could the fact that someone is teaching Reiki harm that person? Well, if that person's employer found out and might fire them for 'doing magic' or some such nonsense then, then, yes, that would be harm I would say.
Now, if the RM asks each student if it is OK to share their name with other practitioners and gets the OK then the RM has done the proper thing. Does this mean no harm might ever come from sharing someone's name? Of course not. But once permission is given the onus falls to that person, not the RM (or doctor or psychologist, etc, etc).
This is what HIPPA is all about in the world of healthcare.
Cheers,
RC