Usually, I'l send something like, "Understand that you've just been pwn'd. You need to work more on your flying skills. I'm a veteran stick and am excellent in both critical pieces of combat flight: aiming my nose AND firing. Better luck next time, noob."
Actually, after experimenting around with it my first year, I decided that I'm usually better off getting separation and putting the lift victor on the bandit. My gunnery's just not that good and my best chance is in not offering a shot, even if it means I get one. I'd make an exception if I were in an A-8 or 110g or something.