Lying, Cheating and Stealing is NOT Conservative.
I posted an article in Politics, I think yesterday, that gives a fairly detailed history on this issue. Seems the "conscience" clause has been in place for approx 100 years and with the exception of 1976, when Goldwater supporters changed the convention rules and required block or unit voting, all delegates have been able to vote conscience. There are a number of court cases cited in that article that conclude that states' laws cannot supercede a private political body, so any state that requires unit voting is not applicable to the nomination.