Again, I watched a girl struggle to work two fingers into her hip pocket. Even if they are stretchier, some of that stretch will have been taken up when she buttoned them.

And knowing the world's factories the way I do, I'm sure there's at least one clothing manufacturer out there that makes (or made) both long jeans and hot pants to mostly the same pattern, ie the jeans are just ankle length versions of the shorts, and to save money on tooling they use the same pattern of pockets for both.