Yes, this may not prompt people to vote for Trump, but it will almost certainly prompt people to vote against Cruz. Overall, I think it may suppress voter participation. If I'm an unregistered voter in Iowa that hears about this my thoughts are going to be, "Why in the hell should I put my name and address in a database that's going to be used like this?"
Trump picked the right election to throw his hat into the ring.
Better pray that Trump has really converted from his past. If not, then the nation is pretty much doomed.