Microsoft has played down a feature in open source rival OpenOffice.org that removes some password protection on Office applications. When users open someone else's Excel file in OpenOffice.org's Calc (the OpenOffice equivalent of Excel) it removes any password protection applied to cells and worksheets by the author, so that hidden information can be read, edited and saved. Story continued here
Why should they be concerned about it? There are open-source tools that can remove the password protection from Windows, I guess protected Office docs are small fish.