A Microsoft Word document is probably "source code" rather than "object code": people do edit Microsoft Word documents, and people don't usually do automatic translations into Microsoft Word format (though they do sometimes, for example when exporting from another word processor).
Anyway, I don't think people distributing Word versions of free documentation is likely to be much of a problem in practice, so I would advise against concocting dodgy clarifications of the GPL that attempt to prohibit this practice. Distribution of optimised PDFs and the like without providing the corresponding source is clearly disallowed by the GPL. Edmund
