According to s18.104.22.168 of ECMA 376, as found at ,
If the parent structured document tag is of type rich text or document part gallery, then [the data binding] property shall be ignored.
So it makes sense for dbe to try to do graceful degradation.
But with Word 2007, it actually isn't necessary. Word 2007 does in fact honour the binding on a rich text content control (contrary to the spec) - whether its one with an explicit w:richText element, or one with no type (which 22.214.171.124 says amounts
to the same thing).
What you can't do with Word 2007 though, is invoke the SetMapping method - as documented on MSDN.
I don't know how Word 2010 behaves (yet...).
cheers .. Jason