Trump definitely won’t take the bait. Childish or not, he’s using the strategy because it has been working.
If Cruz challenges Trump to a series of real debates, Trump would be a fool to accept. His problem would be to figure out how to chicken out without losing face with the mob that supports him.
As for Trump's strategy of childish personal attacks and dishonest smears working, what worked on the rest of the field may not work against the most intelligent and articulate person in the race. Ted is not Jeb.