Yep. Every election cycle Republican primary voters fall over themselves to vote for the most pro-open borders candidate. After selecting McCain in the 2008 South Carolina primary, they told the exit polls they didn't know McCain was for amnesty.
The "conservative" South Carolina voters hadn't bothered to study the candidate's policy positions. All they knew was "McCain is a war hero."
I agree. Rush Limbaugh talks about the "low information voters" generally directed at liberals/democrats but I think it applies even more to "conservatives". I don't know how many times I talk to a solid Republican voter about the problems with a McCain or Romney or Rand and somehow they missed all of the information out there about their shortcomings. Where are they getting their information? It's not like this stuff is hard to find.