When you buy new dress pants, why are the back pockets always sewn shut?

(Express - High-Waist Wide-Leg Editor Pant - Herringbone - $98.00)Think about it, it costs more from a manufacturing standpoint to produce and sew in the actual pocket, so we can safely rule out that it's just for "looks". (If that was the case, they would sew a false pocket cover on and call it done.)
Maybe it's to prevent snags along the way or during shipping and retailing? Maybe it's something as simple as it's easier to just sew straight across for another step in the manufacturing process? I just don't know.
I am a proud
College of Textiles grad, but this is something we never covered in
my concentration.
Anyone ever heard the logic behind this?