Do we know if Trump has made any effort to get his own delegates on the ballot? They might not be bound or publicly declared, but it would certainly help him if he got delegates sympathetic to him voted in. The same, of course, goes for Cruz and Kasich too. I don’t know if they’ve worked on getting their delegates on the ballot either. One would think this would be something all candidates would have already done (as they had to do in Illinois—although those delegates were both declared and bound).
You mean the good old fashioned way, Bribe them?