If they can't disprove it, it remains an interesting possibility.

Piltdown Man, for example, (a quasi-scientific claim) was not disproven for a long time.

Most alternative health therapies, esoteric theories, metaphysical concepts, and "New Age" ideas (if one must give them a label like that) have not been disproven by anyone either...just categorically rejected on the instant they are heard and denied out of hand without further ado by people like my pal Clinton who have are under the impression that they already KNOW everything that is real and everything that isn't, thank you very much! (smile)

How like a God, to be so omniscient. The burden of disproof is on the sceptic. If he can't disprove it, he has no way of knowing whether or not it is real. He just has an opinion.