Can one have preroughening of vicinal surfaces?

We discuss the possibility that, besides roughening, a vicinal surface could display preroughening (PR), and consider the possible mechanisms for its promotion. Within the framework of a terrace–step–kink model, it turns out that a PR transition is possible, and could be induced by a short-range repulsion between parallel kinks along the same step or on adjacent steps, or even by some kind of extended range step–step repulsion. We discuss the possible relevance of this phenomenon to the anomalous roughening behaviour recently reported for Ag(115).