It always takes two to HO.
HO should always expected from the enemy, just like everything else, as there is no such excuse as "I thought he'd fight honorably and not engage in a HO". This game does not simulate a sports competition. It simulates war machines and their clashes.
In the air, anything goes(except exploits and cheats which is something outside the boundaries of things which can be accepted) - there's no such thing as 'honor' in tactical decisions.
...
If you see a Ho coming, avoid it. There's no such thing as 'unavoidable HO'. Nobody put a gun against your head and demanded you point your plane's nose against his nose.
If you are forced into a situation where you are exposed to the other guy's guns head-on, it just means you didn't take the adequate steps to prevent from something like that happening in the first place. Your mistake, no one else to blame.
Besides, most HOs are easily avoided. An effective HO is very rare unless both opponents are serious about landing a shot in such a situation(in other words - suicidal). If somebody actually puts in a lethal shot against a plane moving away from a HO, with such high closure rate and short time to react, by every right he earned that kill.