People complain about being bnz'ed I think because the cold hard fact is there are two possibilities.
1. That P-51 knows what he is doing, and he bags you.
2. If he knows what he is doing but is having a "bad gunnery" night, you probably aren't going to catch him once you equalize the E. Even if the pilot is terrible, he will probably be able to dive and run successfully. Thus for the bnz'ed, it is mostly risk with little chance of being rewarded.