I once belonged to a church which brought in a consultant to help us design a growth strategy. I can recognize a Delphi Technique when I see one. They broke us into groups, with a "helper" in each group, and the conversations were all steered in one direction. When suggestions were solicited and captured on big sheets of paper, some of the suggestions were written down, and others were sort of "forgotten" and not quite captured as the conversation quickly moved ahead.
The kicker?
The professionally printed brochures which captured "our" decisions arrived by US mail the next day.
I never went back.