Here's a scenario.  Suppose you come across an unknown collection of CAD files containing everything in the book: assy's, parts, drawings, etc.  All you know is somewhere in this mix is a top assembly containing everything.  File names and such don't give you any clues to which assembly that might be.  Is there any way to determine the Mother of all Assemblies without opening each assembly in sequence.  Or is there a logic trick to find Mama by opening the smallest number of assemblies?