My understanding is that the caucus votes are by secret ballot. It is the democrats that do that. But yes, a very persuasive speaker can sway caucus goers. Or given the known behavior of the establishment leaders in Mississippi and in Virginia, and other diverse places, a lot of fraud and manipulation and downright lying was going on. We know for instance, that the Cruz campaign lied about Carson’s withdrawing — a truly Romney-esque lie! I am quite certain that the elites don’t mind a Cruz win, they are going to take him out at the convention over his eligibility issues and give his delegates to an establishment (Bush?) candidate. I thik they will do the same with Rubio.
I think a huge thing that no poll could predict was Trump supporters willingness to speak at the caucuses. There were several in which Trump couldn’t get anyone to speak for him.
No, we know no such thing.