BOS clarification?

I'm having trouble matching up what Eliot and Steve are saying about BOS
with what I know from the 1992 version of 10744, section  In part:

  A bounded object set can be determined authomatically by the HT engine
  by constructing an "entity tree", starting with the SGML doc entity of 
  the hub doc as the root.  The entity tree includes external entities
  declared in the hub doc, then external entities declared in those
  entities, and so on. ...  A limit can be placed on the depth of the
  entity tree by the "bounding level" att of the hub document. ...

Does this not mean that every external entity declared in the hub doc
(and every external entity in those entities) is part of the BOS?  And
might it not be the case that I declare as entities in my hub doc
certain public text (part of the US Constitution, for example) that
are not part of my copyrighted intellectual property?  (I might
declare them for the use of links that refer or traverse to them,
rather than for transclusion.)  

The bounding level att works only when my work happens to end at
the same level throughout, so appears not to be a solution.

So isn't BOS applicable to the problem of defining the extent
of my intellectual property/literary work only if I can contrive
not to declare as external entities anything that doesn't belong
to the work?

    Terry Allen    Fujitsu Software Corp.    tallen@fsc.fujitsu.com
"In going on with these experiments, how many pretty systems do we build,
 which we soon find outselves obliged to destroy?" - Benjamin Franklin
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