I have read somewhere that it began as a short science fiction story, but haven't tracked it down. It is an interesting tale.
Whether or not it is "true," it raises a question that needs to be addressed, namely how is it that people (mostly) appear to be returned safely to their own time (if not to the same location, given that they might have moved about during the slip)?
http://spacetimeslip.wordpress.com/2012/08/27/a-double-through-the-...
Well, there are those who don't return to wherever it is that Universe has transported them to. The one's that return are there undoubtedly to inform us that elsewhere exists somewhere, and somewhere is where we will find the lost ones. Why Universe operates this way, seemingly randomly sending some to neverland and others back home is a mystery with a design.
Universe undoubtedly has many secrets which I surmise are linked to the reason for our creation. In my opinion, humans represent an evolving awareness of complexity which they are themselves created from, and combined with our physical dexterity we also do create in ways no other life form we know of is capable of doing.
This implies that Universe wants us to succeed because it has notions of what it's creations are intended for. Universe is itself like a growing child, creating amusing toys out of clay. As a child the greatest gift my parents ever gave me was modeling clay, and together with my other brothers we would sit at the kitchen table and make our child fantasies in to reality. There really is nothing quite like clay for creating instant 3D reality. Anything imaginable is possible with modeling clay. Elephants to tanks, to people to space ships, all it takes is the desire and will to create. These are primary qualities that all children begin life with.
We are the progeny of Universes' creative dreams. Living clay models born in fantasy to act creativity. It is one of our true purposes for existing. Along the way we humans have picked up some passengers whom seem to have used their own creativity to catch a ride with us to who knows where. These passengers are no doubt not accidental but there for us because of what they are themselves; the living creations from which we ourselves sprung from: Our animal linage.
Our species is of course a source of endless entertainment, but Universe must have some issue it want's us, or intends for us to deal with. I think Universe intends that we are to act as a kind of helper, a proxy agent in the grand design, we are no more than microbial life forms at a cosmic level acting then as bio-bots and tools in that context.
To answer what concerns Universe maybe we need to understand what is life to Universe? It certainly involves what we ourselves experience as living beings, but on the Cosmic level of Universe what could concern Universe enough to create a creature like a human? What does it want from us? Does it want to end it's own life, does it want us to help it live, is something threatening the life of Universe and if so what would it be?
Time is a critical part of Universe obviously and these things we are blathering about are undoubtedly tied to our destiny as creations of Universe. As to the Tokyo traveler of 1954, stories like this one are either manufactured, or else they are representations of reality put in to a science fiction context in order to communicate a known truth in a cloaked manner. Could be either one, but considering what we think we know about time, such stories are theoretically possible.
Now I know I'm droning on here so I will try to cut this off, but referring to the illustration of the Minkowski Space-Time Continuum, imagine that the intersection of the past and future light cones is where you are now, because you are there, and so now imagine that going backwards or forwards in time (doesn't matter which way) follows a trajectory that's determined by your choices. In other words, how you live creates a curved path or twisted path intersected at each point in time by the moment you're living in.
As you move forwards or backwards along the time path, you're also exchanging a point in this path to make a progression which is going to be moving outwards somewhere's on light cones of time which are above or below. A little hard to follow I know, but it simply means you've gone from the center point to a point somewhere's away from center in the cones above or below. Think of this as sort of like the 3D chess boards you've likely seen. However the idea here is that if you fall into a hole in this matrix you could end up with the situation described by the fictional story.
Now of course I'm no Hugh Everett, and I have issues with quantum mechanics and quantum theory in general, and the many worlds ideas of Everett were created as responses to the then unexplained double slit experiment. Something which I, at least, feel has been now been explained quite logically. This doesn't necessarily mean the concepts of many worlds is wrong, but it does mean that the quantum explanation for the double slit experiment is wrong, and that means there's a heck of a big hole in quantum physics.
https://en.wikipedia.org/wiki/Many-worlds_interpretation