The Mass Psychogenic Theory is one proposed in the 1960s by a researcher in the Contemporary Offices.
The human mind is as tangible as its body; the strong belief and emotional resonance of a person or persons can create phenomena that affect our material world
It has been hotly debated as a chicken or egg problem. It's very nature makes it difficult to prove one way or the other: do these beliefs create these veiled phenomena, or do these rare occurrences plant a seed in the mind of the occasional observer? Forces beyond our nature and understanding effect us in often subconscious ways, so it doesn't defy the possibility they subtly make their existence known to small and fringe groups.
For now this remains a theory yet the powers that be feel its not unwise to respect the concept and avoid the potentiality of disaster.