Haha...
My thesis is that GOPers, being the savvy, humble folk we are, are much less likely to respond to a pollster than independents or democrats (sinch the polls are continually biased against us). The former will go through with it because they're inherently wishy-washy, the latter because they're obnoxiously egotistic and obviously being asked poll questions feeds into that mentality. It'd be interesting to conduct an informal poll here on FR to see what the telephone-answering-especially-relative-to-pollsters habits of contemporary GOPers are.