It is hard to believe Kerry would do something like this--not because he has scruples, of course, but because the fallout if caught could be large. That said, have you considered that there might be HDTV recordings of this somewhere? They would have much better definition than someone could pull off of a VCR recording a standard broadcast.
Though I have no way to be sure, based on the info I have it's looking doubtful that the event was shot in hi-def. I have access to HD-Net (carried both conventions in hi-def) as well as CBS and NBC hi-def stations; none of the three had the debate in hi-def.
But, the increase in resolution of detail vs. what we're seeing online, and what the networks can see on a DigiBeta master (even if not in hi-def), is dramatic.
There also exists the possibility that there are even more camera angles out there that we haven't seen at all.
MM