Two proposals for nested sections

["Paul Prescod" <paul.prescod@blastradius.com>]

Since your concern is preventing arbitrary nesting of narrative
documents, two solutions present themselves: 

 1. Limit the nesting levels to some agreeable level that is "enough
levels" to satisfy most customers wanting grouping and "not so many
levels" as to support arbitrary narrative. This is truly a compromise in
the sense that neither party walks away comfortable that their concerns
are addressed in the general case. This can be easily achieved in a DTD
with e.g. "subsection" and "subsubsection" elements.

 2. Limit the nesting in the out-of-box DITA using formally declared
constraints or prose. In addition, provide a mechanism whereby a
knowledgable specializer can loosen the constraint for their
specialization (not, typically, to allow indefinite nesting, but rather
to allow the creation of grouping elements in the specialization). The
specification can outline the dangers of this loosening and the
situations under which we believe it is a good thing. If we can agree
that these specializers are (in general) knowledgable and trustworthy
then both parties achieve their goal.

 Paul Prescod