What do You think? Inquiring minds want to know.
Mass... experiences like that are very possible and are also induceable. I've been a participant in such experiments. I've been a cause of such experiences. Not to the degree of which you speak in your example, but in smallish groups of a few people.
I'll take a little risk here and give you one example. A while back, three of four years ago perhaps, I visited an old friend, who is an ex-JW and a Christian. We go way, way back and so we speak more or less freely about ourselves. He spoke of difficulties he and his wife has had making ends meet, etc.
I asked him if I could perform a certain ritual for him that would clear some negative influences and perhaps stabilize his life a bit. The suggestion and intent established, I chose a ritual with appropriate symbolism to his belief system and gave him a basic explanation as to how it would go and what he may experience. I explained that he may see some electric blue light begin to emanate throughout various parts of the ritual. In this case it was a banishing ritual that basically entails invoking YHVH, divine energy, and focusing in the middle of a circle, then directing it to the four corners, within a sphere. I darkened the room and lit some candles. At each of the four corners, I guided this divine "energy" and drew in the air celtic crosses, electric blue. Now, I have only ever "seen" the electric blue in my mind's eye, never in objective reality. But I don't tell him this. I focus intensely upon the details though, making all the lines connect, etc. Within each cross, I energized them by thrusting into the center with my hand while vibrating a certain word in Hebrew. By "vibrating" I mean a sort of chant at a certain frequency which helps to lower the frequency of brain waves.
After I finished, I closed the ritual with a standard "thou art the kingdom and the power and the glory, forever and ever, amen", also in Hebrew. The actual words used are not important and some might likely find fault with their accuracy. It matters little in this context.
The results? My friend says he could actually see the electric blue of what I drew in mid-air (remember, I can't). And he told me later that what I did must have helped because soon after, things started to look much better for both of them, financially and otherwise, and he thanked me.
Suggestion and intent, transference of an altered state of conciousness into another person, a theatrical performance including a number of unconscious symbols relevant to the working and to the persons involved. The intended results achieved.
A very charismatic person, I'm sure, could achieve similar results upon a much larger group of people, probably with much less effort and trappings, especially if the target audience is already believers and very open to suggestion!