Trump strategist Roger Stone tells NJ 101.5 radio that even if Donald Trump wins a majority of pledged delegates to the Republican convention, Cruz will utilize "Trojan horse" delegates (who are bound to vote for Trump only on the first RNC nomination ballot) to vote on "procedural" matters in the Rules Committee or Credentials committee to block or disallow certain votes.
ROGER STONE: Unfortunately just because Donald Trump gets the 1,237 [delegates needed to win], doesn't mean we aren't going to have a brokered convention. My sources, who are pretty good in the Republican Party, indicate to me that Ted Cruz intends to work a "rules strategy" to try to euchre this nomination away from Donald Trump.
In kind of a shady, using political trickery and so on, utilizing these Trojan Delegates we have been talking about -- Where Trump delegates, from the results of the primary -- those seats are filled with non-Trump voters, non-Trump supporters who will vote against Trump on procedural issues in either rules or credentials that could be used to take away his majority.
The rules committee could vote, for example, to disallow delegates from states which allowed independent voters to participate in primaries.