The establishment will change the rules if they have to. To preserve the intent of the rule (keep upstarts from messing with the controlled process), they modify the rules however they need to make sure an insider makes it to the floor.
The rules can not be changed now. They constitute a binding contract on which Trump has relied with his own money. Any attempt to change will be met with mandatory injunction launched by an army of Trump lawyers!! You cannot move the goal line after the game has begun. Too bad. Go TRUMP ALL THE WAY!!!They now die by the sword they had but has been taken away and used on them. Their only hope is a third party which I predicted months ago. Who will the run? Bush?
Which explains why only the CRAP people end up with the nomination .. and not the Candidates who deserve to be there.