It’s worth further discussion as to how it could have been carried out, and how many or few it took, that’s for sure.
But, it would be easy enough to backtrack whether or not it took place. Just ask a few hundred Dem primary voters in each contested area where they went to vote. If two in a given precinct went to different places, that enables the list to be reconstructed.
Good point. That’s another means of gathering confirming evidence.
Another thing... the real polling places would be accessible via the internet. Were the Hillary polls only accessible by phone, or were they posted on Hillary-run sites?