I try to not steal kills (my score should make that obvious), but too many times I've seen a smoking enemy continue to fly and even shoot friendlies. If he ain't down, I'm shooting. No, I won't jump in front of you, won't try for someone if he's obviously getting hammered, but if he comes from above and I don't see anyone chasing him, I'm going to try to nail him unless he's missing a wing.