The MSDN KB is incorrect.
It says
A user-defined function called by a formula in a worksheet cell cannot change the environment of Microsoft Excel. This means that such a function cannot do any of the following:
- Insert, delete, or format cells on the spreadsheet.
- Change another cell's value.
- Move, rename, delete, or add sheets to a workbook.
- Change any of the environment options, such as calculation mode or screen views.
- Add names to a workbook.
- Set properties or execute most methods.