It is one thing to walk away from negotiations. It is another thing to violate a done deal.
Can anyone find "escape clauses" in the deal all the candidates made with the RNC that allow him to do this?
-- Trump has reneged on the deal he made months ago? --
I'm not sure what deal you have in mind. He refused to sign on to support the RNC nominee, then reversed and signed on. As far as I know, he's agreed to limit his debates to those sanctioned by the RNC.
If he does strike out on his own, I supposed he'd honor the conditions of being excluded from all the future (RNC-sanctioned primary) debates. IOW, he wouldn't try to break the deal, he'd abide by its terms.
Debates are not required for candidates. Paul refused the previous debate because he wasn’t on the main stage but is scheduled for Thursday’s because Fox put him on the main event.