I would prefer
Root (Useful | NotUseful) #IMPLIED
Most DTDs have a number of useful potential roots and a number of
not-so-useful ones. By providing a default value one way or the
other, you force me to override it on a substantial portion of my
elements.
Another option is to just say that this is a suggested root:
Root (Suggested) #IMPLIED
For DocBook, for instance, there are many elements useful as roots,
but I might only put Root="Suggested" on <book>'s declaration.
-Chris
-- <!NOTATION SGML.Geek PUBLIC "-//Anonymous//NOTATION SGML Geek//EN"> <!ENTITY crism PUBLIC "-//O'Reilly//NONSGML Christopher R. Maden//EN" "<URL>http://www.oreilly.com/people/staff/crism/ <TEL>+1.617.499.7487 <USMAIL>90 Sherman Street, Cambridge, MA 02140 USA" NDATA SGML.Geek>