I've had friends who do this. I think as long as the meals are reasonably close together (IE, a dollar or two, splitting is fine)..but I think people should be respectful that if you arent' going to stuff your face, why should you pay for someone else's meal.
While we're ranting, I love when you take someone out for their birthday, and this is someone you go out with a lot, and then when YOU are treating, they order more than they ever would order when it is just the two of you. Taking advatange much?