Let me clarify the rules about bounded delegates. They are only bound on the first ballot, and some states up to the second ballot. On the third ballot, all the delegates are unbounded. Those are the rules. So smart candidates work on delegates to switch after they become unbound.
A Republican National Committee Standing Rules Committee member told the membership Friday that convention delegates are not bound to cast their votes at the convention according to primary vote results in the first round of voting.
Curly Haugland of North Dakota, a long time member of the RNC Standing Rules Committee, sent a letter to the RNC membership at large about this issue. He explained how he came to the conclusion that all Republican delegates who participate in the 2016 Republican National Convention are unbound on each ballot round, including the first.
Lining up previously Trump-committed FIRST BALLOT delegates is what Cruz is doing.