What if they are told about multiple universes, when the evience of such things is as thin as butterfly wings, as Stephen Hawkins would have it? Or that the polar ice caps are melting because of SUVs, as Al Gore would have it?
The multi-verse concept right now is just an unproven theory. Altho it certainly could be true, but it's too early to tell. As far as I'm aware, no one is claiming it to be absolute truth -- yet.
Global warming is a good example of how gullible people today can be, and that's with the benefit of a modern education.
So you can imagine how much more gullible folks would have been 2000 years ago!