It's not only the commission that is in the wrong here.
The UFC knew about this yet they've only told about it to Nick 1 hour before the weight in, which is pretty pointless cause he surely was on point at the time, thus giving GSP an extra, maybe insignificant advantage, yet an advantage.
But how do we know there was any actual advantage given? As you said, this video was taken an hour prior to weigh-ins. How can anyone here conclude that GSP didn't make 170 come the actual weigh-in? For all we know, the UFC was worried that GSP might
not make weight, issued this statement to Diaz's camp, only for St. Pierre to come in at 170 regardless. The amount of people here assuming that GSP came in at 170.9 when no evidence points to it is astounding. As I said previously, we certainly don't seem to have many lawyers here.
Was UFC in the wrong for allowing this exception? Is there a fishy loophole in the Quebec Commission's guidelines? Both may very well be. But was this 'allowance' ultimately taken advantage of? None of us has any clue.