Okay... I can almost buy the "gravity defense". It sounds somewhat logical, and I tend to buy "button fly" for this exact reason.

Problem is a lot of the time I am in a rush to get out of the car... friends are waiting for me, teasing me about my "man-bag" and I don't always check the integrity of the pouch zipper. I also seem to prefer the side handle... It just looks a little less like a "european carry-all" that way.