Determine access authorization for another user?

I'm just getting started with Box.  I am building a tool that needs to be able to determine if an arbitrary user has access to a folder.  My app is running as me, klaird, but wants to know if another user, rsmith, has access to a folder

The only way I see to do this (but have not tested) is to get the collaboration IDs for a folder then step through them, checking accessible_by for the user of interest.  Is that a viable way to do it?  Is there a better way?  I'll be running this on several folders.

Thanks.

--kyler