I wonder if people who support Trump are hanging up on the people taking the surveys. I also wonder these polls which show Carson ahead have questions considered to be agenda driven. Which is why the people may be hanging up when called. The MSM networks and colleges seen to have the ones where Trump is behind, when it makes no sense. Has to be a reason more than just jimmied sampling.
If I don't recognize a number on caller ID I google the number before blocking. The Carson campaign called every day for several weeks (different numbers) and they are all blocked so I am one that they can't poll. Seems a lot of us do the same. They were consistent, I'll give them that.