A simple lock which prevents reordering of book documents should be a no-brainer addition to InDesign to prevent accidental re-ordering of chapters (and subsequent renumbering / overset pages and all those other things which are a PITA when they happen at the wrong time!).
Alex, I totally agree with you, as it is very easy to move the chapters. And by today is 03-June-2013, and that change was not implemented since you wrote this message.