I didn't notice anything done by Romney. I think It was one of two things )or a combo):
1) At the debate they were also showing it (as it appeared on Fox News) on 2 huge projection screens on either sides of the stage. The laugh occurs when there is a split shot of McCain/Paul. From the audience's point of view, I think people thought it was highlighting a weird look McCain is giving Paul. In other words, I dont think there was a significant reason there was a split shot there, but the audience thought that there was a reason, and couldn't really tell if McCain was making a weird face, so they figured since McCain is being shown during Paul's time...it must be for a reason.
2) I think it also has a lot to do with the anti-Ron Paul crowd. It comes right after he makes his comment about Iran, which he was ridiculed all night for.
We do have a problem guys...maybe this event was just for "hard core" supporters. But a lot of people that were there think Dr. Paul is the laughing stock of our party. Everyone knows I don't agree with that, I think he is the smartest man in Washington. But, people are so brainwashed by Fox, that anything he says is just "funny".
We need to change this. Somehow, im not sure how...we need to look at how these ideas Ron Paul has have been right in the past. We need to pound home that the idea of nation building is all a big "flip-flop" in the party.