I think I can explain...The focus group is all locals, and these are republicans for the most part.
Did you here the boos when Trump was the only one who refused to pledge support for the nominee, whoever it might be?
To a Republican, that evokes memories of Perot and it drew their ire. (and in the focus group it drew their fire)
It just is what it is...Trump has already been in trouble with this third party crap before, and here it is again.
This "Third Party crap" is a completely manufactured issue by the GOPe. They are using it as a weapon against Trump. He is not initiating any of this. It is so transparent.