Reiki Belief System?

     Nearly a year ago at a family party, during a discussion about Reiki, one of my aunts said to me, "I was told [by a Reiki practitioner] it wouldn't work for me because I didn't believe in it."  She spoke of Reiki as though it were a deity - a belief system - because of what she had been told by her friend.
     What she was saying was, "Since I don't believe in Reiki, it can't help me;" a most unfortunate interpretation due to her friend's misinterpretation - and subsequent misrepresentation - of Reiki.
     I carefully told her what I understand to be true:  Reiki is not a religion, nor is it affiliated with any religion.  I chose not to bring the spiritual aspect that can arise from Reiki self-practice into the conversation as that is so personal to each practitioner and had no bearing on the meaning of her statement.

"Reiki is not a religion, nor is it affiliated with any religion."

     Recently, I noticed a statement/comment attached to an update on Facebook from a Reiki practitioner that stated something to the effect of, "You have to believe in Reiki for it to work."  I physically cringed, wondering how many potential Reiki practitioners and/or clients might see that and be turned off because of the statement's religious and, therefore, potentially limiting connotation.
     What do you think?  How were you taught and what do you convey to your clients and/or students?