Wellll....I can say one thing I DO know for sure: There exist nearly COUNTLESS parents willing to orchestrate things like this. It's really sick. Some parents are just fame junkies; some want everyone to think of how "special" their kids are. btw, these "reincarnation" stories are quite prevalent in India--where there's a big audience for them. The kid will say they were the spouse of a certain person in a nearby town, describe the color of the house, blah, blah, blah....
When I was a young man my aunt's son was a year and a half old, and she told all her relatives how her son already knew the alphabet! She would put a paper in front of him and say a letter, and he would supposedly touch the letter--and he DID understand the game well enough to smack the paper when she said a letter--but all the letters were hand written, so they were very close together. When she tried to show me his talent he didn't seem to be doing very well....and then, he got better...and I noticed that she had him firmly by the elbow and was moving his arm where she wanted (and all her loving extended family never thought to look for subterfuge). I STILL believe it's quite possible that SHE HERSELF DIDN'T CONSCIOUSLY KNOW SHE WAS DOING IT!
People have an amazing ability to delude themselves...and I say this as, more or less, a "Buddhist." I'm not COMPLETELY contrary to the idea of reincarnation. I'm pretty doubtful when I hear claims of it, though.
I remember my young man's fascination with all things Tibet--with a tulku around every corner. But doesn't it seem more reasonable that it's just a good way to raise well-trained lamas? Pick an obviously intelligent kid, and train him for the job full-time from the time he's 4-5 years old. Doesn't it seem strange that NO OTHER culture that has embraced Buddhism (including India for the first 500 years after the Buddha's death) has taken note of extremely accomplished masters declaring they will come back, and giving the place, etc., and then rounding up the kid and "verifying" that he's old lama schwama?