Plus also the Romney and Ryan have been drawing more and more people.
Good point. It takes more effort to physically show up at an event. Voting with one’s feet is meaningful voting.
Moreover, as someone on another site mentioned, “not everyone polled actually votes... and most people including myself just let the phone ring when a pollster calls.”
I’m wondering about the great silent mass of people out there who are exhausted and worried about their jobs, working late, and coming home tired and preoccupied. These people are more likely to let that phone ring and instead turn to a book or the Internet. They are less likely to be in a mood to gab — and, as someone else pointed out, they are aware of the possibility of the pollster taking note of their (unfavorable) opinion and linking it to their address.