They way I look at it a true "HO" is when both planes have little to no G on them, and flying right at one another, guns blazing. Or, if one plane is doing that, while the other declines to shoot, maneuvers a little instead to create a miss, and initiates and early vert turn (usually what I try to do, I can't remember the last time I chose to go head to head shooting, I don't fly planes with guns that are made to win those).
However, I will say that when planes are in a fight, be it horizontal turns, vertical maneuvers/looping/turns/whatever, and somebody happens to flip a shot in my face as we pass nose to nose while pulling gee's, I don't get very wrapped up in the whole "oh em gee, he just tried to HO me" thing. That type of face shot is a lot different than a merging HO, at least in my mind. My little Joe A Cheem hit me with one of those last time I flew, and it's no big deal, a completely non HO type of shot IMO (I ended up doing the same to him with a tater the next sortie, well not as close, but close enough). At least the opponent is fighting you and not running, so what if he takes a face shot after turn number 4 or 5 then, that's how I look at it, even though most of the really good sticks will still wait to unravel you, and shoot you up the behind, which is a good way to go IMO in terms of learning how to fly and fight better.
