(as it is using the sessioncontext plugin, etc), a lazy load operation
will use that session by default if the parent object is not
persistent with a session already.
+- lazy loads will not fire off for an object that does not have a
+database identity (why?
+see http://www.sqlalchemy.org/trac/wiki/WhyDontForeignKeysLoadData)
- unit-of-work does a better check for "orphaned" objects that are
part of a "delete-orphan" cascade, for certain conditions where the
parent isnt available to cascade from.