Never underestimate the human capacity for self-delusion, or the orchestration and manipulation thereof. Take a group of people who may already be eager to be part of something other (and in this kind of case, the more really is the merrier, since the group is self-reinforcing), prime them that they're actually going to experience something, and I'd be most surprised if at least a majority percentage don't see anything. What would the odds rise to if you direct them to some action geared to distort their perception; say, staring at the Sun for several minutes?
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'