The standard DA merge is a co-E head on no shot merge. There is nothing unrealistic about it. It's used in real pilot training with the addition of a minimum lateral offset to prevent collisions. It isn't common in the late war main arena but it can happen there too.
In competition dueling the merge is spelled out in the rules and is usually an altitude ceiling, maneuver as you like when you see the bandit icon, and no shot until after the first pass.
