Correct, Randi! However, I think if the diet coke is replaced by apple or sparkling cider,
tea, wine, club soda mixed with some jerk seasoning it should work to impart moistness and flavor. I'm not sure if it is the carbonation or just the liquid that's needed. Steven Raichlen's Barbecue Bible recipe for Beer Can Chicken dosen't explain why beer. Diet coke just doesn't appeal to me with chicken.