After the last version of the "beat up" from 47 Ronin, where every warrior beats the target with a club, Trump should absolutely find a way to not dodge this, but one-up it with a "debate" of his own by buying time in the 1st half hour.
That said, I'm sure the RNC has some poison pill in the paperwork saying if you don't do their debates they can officially remove you from the list of candidates.
