They should be at least nervous. I think Trump is going to vastly outperform the polls; I think we'll see that there are a lot of Trump voters out there who weren't willing to admit to supporting Trump to pollsters but will do so in the secrecy of the voting booth.
thus far there has been no evidence of that. Only evidence of the opposite: people who are saying they'll vote for Trump, but as soon as they get in that voting booth, reconsider that choice. And admittedly, even evidence of that is scant.