One person creates a fantasy and then speaks of it as though it is real.
The next person hears it and believes. They add to the fantasy their desires and speak like it is all real.
Others hear it all and believe. They speak of it all like it is real. They also act together on their shared belief.
After some time, there is always someone who hears it, believes it, and acts on the belief.
Is the illusion now real?
Was anyone a fraud?