Is it intentional that when asking for the IdPath of an item, it is prefaced with the application root?

e.g. it's returning /www/10/51, but if I get that idpath and pass it into a cmsviewer, it doesn't work obviously, so I have to strip off the preceding /www before passing it in.

I understand why AliasPath would return that, but I guess I just expected IdPath to be clean.