|I mean if you either have an eye-witness or more reliable a video (which has been analyzed to make sure it's an actual teleportation shown and not special-effects). But you're right without this you wouldn't know, I'm speaking if the persons caught in the act!!|
I don't think whether or not it's "witnessed" is important at all. Even if you know somehow has been teleported, the whole point of the conversation is if the teleportation itself it would make any difference...would they really be a different person?