Trump indicated that he'd do something like this last week when he made his "I could shoot someone" comment. He committed the media version of that action yesterday.
My personal opinion is that this is entirely tactical on his part. He simply doesn't want to have to answer questions with the Iowa primary on the horizon and the increased likelihood that voters will actually be listening to him. By doing this tap dance he has the media talking about everything EXCEPT his non-existent policies AND he gets to play the underdog card he's been relying on all the time. This move allows him to continue to portray himself as both a political and a media outsider and that's what his supporters have been eating up all along.
Now, as you asked, will it help him? My guess is that it will not. This is a play directly for his base and it will piss off those who were beginning to accept him just because he was running out front and seemed inevitable. My bet is that as long as Cruz puts in a good performance we will see him pick up significantly. I also suspect that Bush will pick up several points after he gently reminds everyone that he called Trump a jerk about a month ago.
I think it will backfire on him.
Nah....
This is exactly the kind of rebel stance his followers will eat up. "**** you mainstream media..."
Whatever he does that day will get more media attention than any one of the candidates in the debate. I see this as one of the most clever moves he's made.
Fact is, the others would look cheap and dirty if they attack while he's not there, all they can do is whine about him not following "the rules"....which is exactly what his followers want....to say damn the rules, we're doing it our way!