Well, so far it looks like the theory is useless. Seems like it's almost the opposite, if anything. I wonder where that idea got started? Of course, this is hardly a scientific study, either, but still, you'd think, if this was a valid theory, there'd be at least some women that it was true for!
Well if you add my rapid labour sister in, she has had lots of stretchies and lots of tearing. But they have always put it down to the sheer speed of her labours. Her body simply never got the chance to even think about stretching naturally.