I’ve been running into this issue lately, where I’m quickly switching between pages as I’m editing a document, and somehow I’ve ended up dragging a page out of order. This is a problem when I’ve got the pages in list view, but it’s not a problem when it’s in thumbnail view. (I think it has to do when I’m switching from the pages tray to another tray and I’m using the scroll button on my mouse.)
It doesn’t seem to be a bug, but rather, user error ( 
) and a lock on the order of pages would help me out a lot.
But even if it were a bug, I’d still like to be able to lock the order of pages.