As much as I dislike the HO, I do feel it is a necessary and important ingredient to have decent, fairly realistic aerial fights. I feel that way for two reasons in particular.
One, there should be (IMO) a "penalty" or deterrent for allowing your opponent to acquire a gun solution, or for giving him one. Put yourself in harms way, and you should suffer, simple as that. In this case, what I'm referring to are the guys that will pull their immelmann early, showing you their belly, or other similar maneuvers. They're counting on you to be polite and not shoot, and are attempting to take advantage of that and get around on you. IMO, that's just as cheap, if not more-so, than the HO shot itself. To not shoot them would be wrong. They need to learn that exposing themselves to taking hits is a bad idea. To not shoot would lead to them believing that maneuvering like this is OK, proper, and effective.
I NEVER enter a fight looking to shoot HO-style, but will rapidly change my mind in this situation- out of a sense of duty. Sure, I'm upset that they would force me to send them to the tower before we could really even get started, but to not do so would be a dis-service to my opponent and to the overall quality of fights in the game. So, I'll sacrifice the quality fight I'd hoped for in order to help my opponent along on his path to higher ACM knowledge and higher quality fights in the future. To not do so would lead to lower quality fights in the future. I'll "take one for the team" here, and shoot him with a cheap shot.
Two, the HO taboo should not be used like a "goal" in a game of schoolyard freeze tag. I often see pilots pull into an intentional HO with the (apparent) thought that this would force me to not shoot. An example would be the low guy pulling HO into my dive attack. He's relying on the "Don't shoot me, I'm HO and that would be taboo!" defense, rather than on a legitimate ACM defense. IMO, this guy also needs to be shot. Sure, I'd rather pull up and delay my dive for a few seconds and shoot him as he hangs and falls off (and I usually do). The problem is that he learns that this is an OK, acceptable, method to defend himself, when in reality there are several better options. So, again IMO, not shooting this guy is a bad idea, and encourages behavior that could lead to lower quality fights in the future. So, I'll shoot him if I can do it without taking hits myself. Allowing him to shoot me down in this situation would be very negative. He'd be given a positive re-enforcement for bad behavior...
Don't think I condone the HO attack we see so often in the MA's- I don't. I just think that in some situations it's a necessity to maintain or advance the quality of our aerial fights.
MtnMan