[Bug 5438] confusing sentence in 5.2 SML-IF Documents

http://www.w3.org/Bugs/Public/show_bug.cgi?id=5438

           Summary: confusing sentence in 5.2 SML-IF Documents
           Product: SML
           Version: LC
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Interchange Format
        AssignedTo: cmsmcq@w3.org
        ReportedBy: popescu@ca.ibm.com
         QAContact: public-sml@w3.org


Section 5.2 SML-IF Documents, 4th paragraph, last sentence :

An SML-IF document MAY form a valid SML model but it is not required to do so.
>>>Various uses of SML-IF may define requirements with respect to model
validity and the interchange set, but this specification does not.<<<<

I find this sentence completely confusing; an example or some more information
is needed here.