I see two issues here... maybe three.
I would consider it common courtesy to be asked if I would like reiki to be added to a massage, any client may well have no desire to receive reiki, they have afterall chosen to go for a massage.
If the practitioner thinks that reiki is a part of massage then one would have to question the quality of training which would allow such confusion.
And then there is this thought... licensing. There is a possibility that more states (like Florida has done I believe) will dictate that reiki is a part of massage and require anyone to be a qualified masseur/masseuse to be able to practice reiki for payment. This is not a place we want to be in my opinion. Could the training of reiki within massage be the thin end of this wedge?
Stylus
