if the sphincter that jumped into the fray is the one that is shooting you in the face right off the bat without any attempt to get a different firing solution, then yes.
I will admit on occasion I've been that sphincter. It's not my preferred way of fighting, but when they're taking too long playing with their food, sometimes I choose to give them a hand. The thing is, as I stated, what can start out as a rear attack can change aspects many times on the way down. Yes, sometimes when I've done this I was coming in from ridiculous alt too... I am a bad bad man.
In my defense, I usually only do something like this lately when defending a goon or something along those lines.
The point is, you can either choose to abort the shot, or take it and possibly put down the bandit. The way they're facing at this point is pretty much pointless IMO.
Think of head-on attacks as jousting. Two knights (so to speak) sinking spurs and aiming their lances at each others chest.
In your first example you are describing someone avoiding or attempting to avoid a head-on attack. So we have one pilot attempting and one avoiding. At that point, there's no joust. If the attacker presses and manages to hit, it's a failed maneuver on the defenders part. The key word is defender. That pilot went on the defensive. A head-on attack (joust) involves no defensive technique applied.
But the guy that takes the shot is still carrying through on his HO, regardless of what the other pilot is doing. You're technically correct, which some say is the best kind of correct, but I still consider it a HO if a guy comes in front quarter guns blazing with no thought for any other kind of set up. If the second pilot had cooperated, it would have been a ho.
Wiley.