They are voting to see who will get the delegates vote on the first round. It matters not on whom they will vote for on the second ballot, which there will not be one. So who cares if they are for Cruz or anyone else? It may matter for the platform and rules committees, but not for who is going to be the nominee, i.e., Trump.
Cruz is still up to his garbage because he wants to influence the platform and get a prime time speaking slot. He’s wrong on both accounts. The little weasel has no intention of supporting Trump so he might as well stay at home.