the nylon piece on the PAC can't slide up and down as it is a loop of nylon with one end of it stitched close and onto the pad that sits under the buckle. I have several friends with PAC bags and was able to try them out first. Bagaboo copied the design and I have seen it on a few Freight bags as well as some Australian company's bags.

Chrome has more recently hired some long time messengers so hopefully that is what is helping in their improved bag designs.